TCCoA Forums banner

1 - 20 of 50 Posts

·
Registered
Joined
·
1,164 Posts
Discussion Starter #1
Last Saturday, it was about 105 degrees here in Phoenix. I was driving my 1997 Thunderbird LX Sport 4.6 liter V-8 around and had some trouble with it. I'm wondering if anyone has any ideas as to what was going on.

The problem I had was, and this occurred about 5 times (for about 15 seconds or so each time), is that as I was accelerating (moderately) up to a cruising speed of about 45-50 m.p.h., and just about as I reached that speed, the car started vibrating/shuddering, as if the engine was mis-firing, and it felt like it was kind of losing power. I kind of backed off the throttle slightly (I was trying to baby it so it wouldn't break down and I'd have to get the thing towed; it has about 190,000 miles on it), and after about 10-15 seconds, it would start running normally again. Also, while this was happening, I noticed that the PCM must've dis-engaged the A/C compressor clutch, as the air started blowing hot out of the dash vents. As soon as the car started running normally, the A/C would start blowing cold again.

I reached my destination just after this happened for about the 5th time and shut the car off for about 15 minutes. When I came back out, it started right up, so I drove about 5 miles to Walmart, without any further incidence, to do some shopping. I was in Walmart for about 30 minutes, and the car again started right up when I was ready to leave. I drove about 6 or 7 miles to my apartment, and the car again ran fine.

I did notice, however, that my temperature gauge was reading kind of high as I was driving around Saturday, about 3/4 of the way up, but still in the "normal" range. I say it was reading kind of high because I had some cooling issues last year during the summer, and I replaced a number of parts. Since that time, the gauge has always stayed below the 1/2 way point, even when it's been quite warm here. Specifically, I replaced my electric cooling fan last summer, after the motor burned-out and my engine overheated (I realized something was wrong because my A/C kept cutting out & blowing hot air out of the dash vents, due to the PCM dis-engaging the compressor clutch when the coolant temp was getting too high). After replacing the electric cooling fan, the car was still running pretty hot, so I ended-up also replacing the radiator, the thermostat, and flushing the cooling system & replacing the coolant. That seemed to totally cure my cooling system woes until now, it seems, although I'm not entirely sure this latest issue I had was due to the engine running too hot (although, since the A/C was cutting out like that, I'm thinking it IS due to heat issues).

One last thing I feel I should mention - when I had my overheating troubles last year, and I changed my engine coolant, I bought a bottle of something called "Water Wetter"; I'm sure most of you know it's supposed to lower your engine coolant temperature a bit after you add it to your cooling system. Well, I never added it to my engine coolant until last month, because at the time of replacing my coolant last year, I had put enough engine coolant in the recovery bottle that the level was high enough that I couldn't put anything else in there. It wasn't until last month the level had decreased enough to add the "Water Wetter"; however, I noticed the very next day, after adding the "Water Wetter" to my cooling system, my temperature gauge seemed to read significantly HIGHER than before I added the "Water Wetter" I'm not sure why that would be.

The only other thing that's been done to the car recently is a Firestone store replaced my electric fuel pump in the gas tank, after it failed and I had to have the car towed.

Anyone have any ideas what could be going on here?

Thanks,

Dennis
 

·
Registered
Joined
·
1,164 Posts
Discussion Starter #2
I should also mention that, within the last 3 years/25,000-30,000 miles, I've also replaced the upper & lower radiator hoses, as well as the water pump.
 

·
Registered
Joined
·
1,488 Posts
Any service done to the transmission recently? Fluid change?
 

·
Registered
Joined
·
1,164 Posts
Discussion Starter #4
No; I had a new torque converter installed (due to the dreaded torque converter shudder) and my transmission rebuilt at DirtyDog Performance, but that was way back, like, in January or February of 2010, when I was still living in Ohio.
 

·
Registered
Joined
·
1,488 Posts
Ok nevermind then lol

But this
I was accelerating (moderately) up to a cruising speed of about 45-50 m.p.h., and just about as I reached that speed, the car started vibrating/shuddering

Is exact signs of a tc shudder, but i dont think 3 years of use on a recent one would shudder unless your fluid is too hot constantly
 

·
Super Moderator
Joined
·
9,245 Posts
I still wouldn't rule out oddities with the trans or converter. Alan doesn't have a flawless record (ask me how I know).

Anyway... If you've got more than 20-25 thousand miles on the fluid, it needs to be changed. Heat is what kills trans fluid, and your driving the car in a hotter climate only increases the need to change the fluid more often.
 

·
Registered
Joined
·
1,164 Posts
Discussion Starter #7
FYI, the trans has synthetic fluid in it, but I know that it still needs to be changed occasionally. And, I know what torque converter shudder feels like, and this wasn't like anything I've ever felt before.

And, if it's trans related, why would the A/C be cutting out during these episodes?

Dennis
 

·
Registered
Joined
·
5,412 Posts
Rule of modern automotive cooling systems. The coolant must go somewhere. (Ex. Leak via internally to the transmission, internally to the engine, or externally of the system). I would check the oil and transmission to be sure there is no water contamination and check the coolant system for any oil floating in the degas bottle. When my mothers 95 (earls old 95) started overheating I found the coolant low and with a red tinge of oil floating in the degas bottle. I changed the radiator due to an internal transmission cooler leak and changed the transmission fluid and never had another overheating problem. Judging by the misfire episodes my guess is you have either an original all plastic intake leaking coolant, or an intake gasket leak, or a heater hose leak, all of which will have coolant make it's way into the spark plug wells and misfire.
 

·
Registered
Joined
·
1,164 Posts
Discussion Starter #9
I replaced the Dorman intake manifold on my T-Bird in 2010 with a Ford OEM intake with aluminum crossover, and also installed new Ford gaskets at that time. I didn't do anything to the heater hose, though.

Dennis
 

·
Registered
Joined
·
1,164 Posts
Discussion Starter #11
first thing to check for the misfiring under load is the spark plug wires, spark plugs, and spark plug wells. Have you checked any of these three things?
No, I haven't checked anything yet. I actually haven't left my apartment since I got home Saturday evening; I have an injury to a muscle in my leg that hurts really bad (it's just starting to feel better now). I drive a tractor-trailer for a living, and I couldn't work on Sunday, like I'm normally supposed to. I am, however, about to go into work in about an hour, and I'll open the hood and check some things out when I return from my route in the morning.

The spark plugs and plug wires were replaced (Autolite plugs/Motorcraft wires) at the same time I replaced the intake manifold, which was about 28,000 miles ago (approximately February/March, 2010). I'll have to check the plug wells for coolant.

Dennis
 

·
Registered
Joined
·
1,164 Posts
Discussion Starter #12
Hey, I should probably mention, because I just thought about this, my car was doing something a little unusual for a while before it started acting up - I was experiencing some spark knock or detonation under moderate load. I say unusual because it really hadn't exhibited any detonation since last summer out here when, coincidentally, it was really hot out (hot in Phoenix - go figure!), but I attributed that to my catalytic converters being shot (I had to replace them to get my "Check Engine" light to go out, so I could get AZ plates) and my DPFE sensor for the EGR system being bad (and I had just replaced that a year earlier - that's what I get for using an AC-DELCO part)!

Anyway, the amount of detonation I was experiencing on Saturday was, I would characterize, more than light, but less than moderate. I don't know what was causing it, but I'd be willing to bet it's related to the problem I experienced.

When I drove to work last night, the car ran fine - but it was much cooler outside at 11:30 p.m. - ONLY 90 degrees! :) However, I did notice more detonation.

I'm heading back to my terminal right now. Once I'm back, I'm going to visually inspect some things, including the coolant/oil levels and conditions.

Dennis
 

·
Super Moderator
Joined
·
9,245 Posts
Start with the basic tune-up items first. Plugs, wires, MAF sensor cleaning, fuel filter, PCV, vacuum leaks etc. You can run higher octane to keep it under control until you can fix the root cause.
 

·
Registered
Joined
·
1,164 Posts
Discussion Starter #14
first thing to check for the misfiring under load is the spark plug wires, spark plugs, and spark plug wells. Have you checked any of these three things?
I checked all three of those things (well, I didn't actually remove any of the spark plugs and look at them - hey, I've been up since yesterday morning, and it's HOT outside!); the plug wires are Motorcraft OEM wires replaced within the last 28,000 miles, as are the Autolite double platinum plugs I installed at the same time (I replaced those two items, as well as installed two new Motorcraft coil packs, at the same time as I changed my Dorman intake manifold over to a Ford non-PI intake with an aluminum crossover). The plug wires all LOOK to be in good condition (aren't even really that dirty on the outside), and I pulled one spark plug boot off and looked down in the well - dry as can be, with NO signs of coolant leak anywhere. I even used a flashlight to look all over the engine, particularly around and UNDER the intake manifold and spark plug wells, and I could find NO evidence whatsoever of ANY fluid leaks - oil OR coolant! I checked both the oil and coolant levels, and they were fine, and neither showed ANY contamination with other fluids at all! The coolant was as bright green looking as new coolant from the store, and the oil looked like I had just changed it (even though it's about due for a change)! I saw NO loose wires/connectors, nor did I see any loose hoses or any evidence of vacuum leaks.

I started the car up and verified that the electric radiator fan came on with the A/C, which it did (it should; it's a new one I just installed last summer, and I remember verifying at the time that it operated at both hi & lo speeds, as it's supposed to).

In fact, I was struck by how smoothly the engine idles on this car - better than some NEW cars I've been in, and certainly impressive for a vehicle just about to turn 191,000 miles!

The only thing I noticed is that it appears the trans may have too much fluid in it, although I only checked it cold, or before I started the car. It clearly came up almost 1/2" OVER the white plastic thing on the end of the dipstick, so I may just go have the fluid and filter changed somewhere. The fluid itself looked great - a bright, pinkish red, and it seemed very clear (no sign of contamination, that I could see). I'll have to check it again when it's warm, with the motor running - isn't that how you're really supposed to check it?

Dennis
 

·
Registered
Joined
·
1,164 Posts
Discussion Starter #15
Start with the basic tune-up items first. Plugs, wires, MAF sensor cleaning, fuel filter, PCV, vacuum leaks etc. You can run higher octane to keep it under control until you can fix the root cause.
Brandon,

The plugs (Autolite double platinum) and wires (Motorcraft) were replaced about 28,000 miles ago (around Feb/March, 2010), and I installed a new Ford mass airflow sensor and Motorcraft fuel filter around 42,000 miles ago (July, 2009), although I've cleaned the sensor a few times since then (the most recent time being last summer). I will clean the mass airflow sensor again, and I didn't realize I changed the fuel filter so long ago, so I'll change it again. I also just checked my maintenance records and see the PCV valve's been in there for about 42,000 miles, so it's time to replace that, too (as well as the air filter)! I'll also have to check all the vacuum hoses more closely, but wouldn't it idle funny/roughly with a vacuum leak? I had it running earlier while I was checking some things out, and was just amazed at how smoothly it idles, especially for a car just about to hit 191,000 miles!

Thanks,

Dennis
 

·
Registered
Joined
·
1,273 Posts
yep, definitely clean that MAF. you could also try to unplug it next time you start having these issues and see if they go away.

fuel filters are cheap, so that also a good idea.

otherwise its rare, but possible you have a weak coil. if you have a know good set, or can get your hands on a good set, swap em in and see what happens.

also have you cleaned off the AC condenser out in front of the radiator lately? sometimes it collects a lot of dirt hair and foliage, blocking airflow. popping out the fan and running a hosepipe sprayer through the rad from the inside out is usually all it takes.
 

·
Super Moderator
Joined
·
11,961 Posts
There's always a possibility that you need new plugs and wires. Just because they are only 3 yrs old doesn't necessarily mean anything. Yea you chose good parts, but there is always that slim chance. Unless you can test them on another 4.6 2V that you know is working.

but wouldn't it idle funny/roughly with a vacuum leak?
Not if the computer already got used to it and adjusted the ISC duty cycle for it. Wanna see for sure? Clear the pcm memory via any one of the acceptable methods, then go start the car. If it idles like normal, then you don't have any vacuum leaks. If it acts weird, it's a leak that the system has not had time to mask, and thus shows up as a funky idle.
 

·
Registered
Joined
·
1,164 Posts
Discussion Starter #18
O.K., I can see how any number of those components could've caused the mis-firing I seemed to experience, or the detonation I'm suddenly now experiencing again, but what I don't get is why the A/C clearly quit working each time, and then started up again as soon as the engine started running normally (something had to be dis-engaging the magnetic clutch on the compressor - the PCM)? It's got to be heat-related, and it's no coincidence, I don't think, that it occurred on the hottest day we've had here in Phoenix so far this year.

I have NO "Check Engine" light illuminated, at least not yet. It was on recently, and the code indicated a bad Camshaft Position Sensor. I replaced that sensor on April 26th, and the light has not come back on since. I was initially worried the PCM had gone bad, as I read about a trouble code indicating a bad Camshaft Position Sensor could sometimes be caused by a bad PCM, but I was starting to believe that WASN'T my problem, since the light never came back on.

I'm REALLY hoping now that this latest problem AND the trouble code for the bad Camshaft Position Sensor AREN'T the result of a bad PCM!

Dennis
 

·
Registered
Joined
·
1,164 Posts
Discussion Starter #19
O.K., I was just reading through some other threads on here, and I saw where some people recommended disassembling the MAF sensor and gently scrubbing the wire - I've never done that. What do you gently scrub it with?

Dennis
 

·
̇
Joined
·
3,701 Posts
O.K., I was just reading through some other threads on here, and I saw where some people recommended disassembling the MAF sensor and gently scrubbing the wire - I've never done that. What do you gently scrub it with?
Cleaning MAF's Sensor Wires

I always use this method whenever a clean a MAF Sensor..

BE GENTLE!


Rayo..
 
1 - 20 of 50 Posts
Top