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I'm troubleshooting some issues with my 97 4.6L Sport. It's had some minor running issues, slow starts, rough idle at random times, and slippy shifts into third gear and 4th when the TC locks.

Symptom 1: All of my shifts seem early with little regard to throttle position, though I can step on the throttle and downshift. At 210,000 miles, my first reaction on the shifting was just a tired transmission, but I have my doubts. (See symptom 2)

Symptom 2: Throttle lag. When quickly tapping the throttle there's a delay before the engine revs. I also noticed the other day that unplugging the MAF didn't hurt the engine's response; in fact for the next few revs the delay was a little less noticeable.

Symptom 3: Lack of power, running out of umph. I realize this is probably related to S2, but the other day I decided to hit a straight stretch of back road and open it up. I laid into the throttle and it got extremely anemic and acted like it was starved. I let off, hit it again, and off it went.

Symptom 4: I do have an active CEL, but it's an intermittent warning about Cat efficiency. If it were easy enough, I'd gut em and install eliminators. I'm not a tree hugger and I don't have to submit to inspections.

Now, to the things I have either checked or replaced. This isn't my first bird, in fact it's my 4th MN12, so I'm familiar with the usual TPS sensor checks and MAF cleanings as possibilities. It has a new fuel filter, though I don't have a gauge for fuel pressure readings to rule that out. Did a recent tuneup with wires and plugs and air filter. I had the trans flushed and had Merc V put in along with a bottle of Lucas Trans Fix.

It still runs and drives, and if I'm nice to it, I get about 23 mpg, but it's just not right. I'm having a feeling a reading somewhere is off and it's triggering all of these issues, I just can't find it without throwing parts at it. I've heard of people using data loggers to see real time performance. Are there inexpensive options out there for purchasing the equipment for this, or do you guys have some other ideas?

I'm determined that these are tied together, but like I said, I just don't know how yet.

Thanks!
 

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Inexpensive data logging - if you have an Android smartphone, or an Android tablet with Bluetooth, there's the little Bluetooth OBDII adapters (usually ELM327 on them). Tied with Torque (Free is good enough, but the non-ads paid version is like $5!) and you've got a data logger for an ODBII car. And since yours is a 1997 ...

RwP
 

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Based on my recent experiences I suggest that you clean the Mass Airflow Sensor(MAF). I made a post about my issues that I solved this way. Its cheap and fast to do and might solve your problem.

Clean the sensor wire with a solvent. Don't try to touch it or manually clean it. Good luck, I hope yours works out as well as mine did.
 

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I'm troubleshooting some issues with my 97 4.6L Sport. It's had some minor running issues, slow starts, rough idle at random times, and slippy shifts into third gear and 4th when the TC locks.

Symptom 1: All of my shifts seem early with little regard to throttle position, though I can step on the throttle and downshift. At 210,000 miles, my first reaction on the shifting was just a tired transmission, but I have my doubts. (See symptom 2)

Symptom 2: Throttle lag. When quickly tapping the throttle there's a delay before the engine revs. I also noticed the other day that unplugging the MAF didn't hurt the engine's response; in fact for the next few revs the delay was a little less noticeable.

Symptom 3: Lack of power, running out of umph. I realize this is probably related to S2, but the other day I decided to hit a straight stretch of back road and open it up. I laid into the throttle and it got extremely anemic and acted like it was starved. I let off, hit it again, and off it went.

Symptom 4: I do have an active CEL, but it's an intermittent warning about Cat efficiency. If it were easy enough, I'd gut em and install eliminators. I'm not a tree hugger and I don't have to submit to inspections.

Now, to the things I have either checked or replaced. This isn't my first bird, in fact it's my 4th MN12, so I'm familiar with the usual TPS sensor checks and MAF cleanings as possibilities. It has a new fuel filter, though I don't have a gauge for fuel pressure readings to rule that out. Did a recent tuneup with wires and plugs and air filter. I had the trans flushed and had Merc V put in along with a bottle of Lucas Trans Fix.

It still runs and drives, and if I'm nice to it, I get about 23 mpg, but it's just not right. I'm having a feeling a reading somewhere is off and it's triggering all of these issues, I just can't find it without throwing parts at it. I've heard of people using data loggers to see real time performance. Are there inexpensive options out there for purchasing the equipment for this, or do you guys have some other ideas?

I'm determined that these are tied together, but like I said, I just don't know how yet.

Thanks!
do you have the stock airbox? remove it, and look for cracks around the edges where the top half is "molded" onto the bottom half. This was the issue and fix for me. the car sucks air through there AFTER the maf sensor, creating a lean condition causing all kinds of codes.

i realized you have a 97... different airbox style on 96-97... check the TPS man.
 

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Rodeo Joe - I THINK that 94lxbird is calling the "violin case" an airbox.

He HAS to - otherwise, it can't be AFTER the MAF, since the airbox (where the air filter resides) is BEFORE the MAF.

Or rather, that's how I'm reading it ...

RwP
 

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If the cats are clogged, that sure won't help accelleration. Would not hurt to throw a fresh set of plugs in there if you have not recently.

These transmissions, without a tune, have a mushy feel (slipping) after the shift to 3rd at low speed as the converter tries to lockup. Also does the same in OD if the fluid is too cold for lockup. It helps to give it more throttle in 2nd to force it to shift into 3rd at 30 MPH or above.

Al
 

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Discussion Starter #9
Sorry for the absence guys, it's been a heck of a week! 11 inches of snow on the ground in a couple of days and I've been laid up with a bad back.

I'll give the MAF another cleaning. It has been a while. T6, that's something that I have tried before. Extra throttle in 2nd generally does give me a more secure shift in to third, but with the shudder that I'm getting now, I'm thinking my TC may have finally given up the ghost. I'm just hoping I can replace it alone without a full rebuild or trans replacement. I really don't want to go there.

The reason I'm looking at electrical is because I'm an IT guy, and my gut just feels like some of this is linked. With everything being computer controlled I know it depends on accurate data about what's going on within the engine and the drivetrain. Maybe I'm overthinking, but that's what I'm hoping the datalogging will show me.

Thanks for the ideas. I'll see what I can figure out, though while melting, we still have 6 inches on the ground, it won't be going anywhere anytime soon. I thought my other birds were bad in the snow, this one takes the cake. Those 3.27's put too much power to the ground.
 

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A full fluid change (torque converter, etc) might get rid of the shudder. It did for me!

Edit: I noticed you had a trans flush. How many qts did they use? I used almost 12, which definitely helped.

Al
 

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A full fluid change (torque converter, etc) might get rid of the shudder. It did for me!

Edit: I noticed you had a trans flush. How many qts did they use? I used almost 12, which definitely helped.

Al
Agree with the edit portion. Pull the trans stick and take a look.

Also if that fuel pump hasn't been changed with over 200k I'd do it anyways.
 

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Discussion Starter #12
Trans fluid still looks and smells good, and the flush and refill did help for a while, but I never expected that to be a permanent fix. As for how many qts, it was a little while ago and honestly I don't remember.

At 200k, I know I'm in for some repairs and perhaps their time has come. I have thought about the fuel pump because there are some times when I have to key it twice before it'll start up. I'm hoping my datalogging venture will help me look at all the stats and point me in a better direction. I'm not in a position to start tossing parts at her, so I have to be careful where I start pouring the cash into it.

Plus, it is winter in the midwest and I try not to subject it to the snowy/icy roads, but tomorrow it'll have to venture out anyway while my Bronco waits on carb parts.

It's an expensive and time consuming hobby having older cars. I just can't stand most of the "new" ones. This 97 'bird is likely to be the newest in the fleet for years to come. Auto engineers lost their minds after that and started unibodying this and hybrid BS'ing that. I miss simple and kick A.

Appreciate all the input here though, I'll be reporting back on this as I work through the suggestions. This will be my first time being able to drive it since I originally posted as I had to dig it out of 11 inches of snow.
 

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Could be the primary cat clogging up. Went through this on a friends 96. Replaced the cats and it ran like a new car.

Has the fuel filter been changed?

And flushing a trans with 200K miles on it probably has helped it along in it's slow death. I know some say it's fine if it's been maintained and you know the maint. history of it, but I've seen flushes kill more high mileage trans. vs. just dropping the pan and draining the converter(if you can). Just personal experience, not necessarily fact.
 

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Discussion Starter #14
I've seen a code about the cats, but it's not coming up now. I only have the primaries, as the third was was cut out long ago.

As for the fuel filter, it was replaced about 9 months ago, but it's cheap enough to do again just in case. I ordered this little dude this morning and should have it by Friday so I can start getting some readings and narrow these things down. I'll probably be gutting the cats soon anyway, so we'll get those out of the way.

I know my trans is probably on its final legs. I'm looking for a decent core that I can jmod and get ready before this one dies. It's on the to-do list for this year.
 

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Discussion Starter #17
Long time, no post. The first OBD II scanner I got was a bust, had to send it back. Picked up a new one that finally works and was able to pull some codes and do some logging. Most interestingly, I got a camshaft position sensor code which seems to explain an awful lot about the recent issues. Now just to learn how to read this log.....
 

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I'd replace or remove the cats. The symptoms just keep saying its either not getting airflow or can't get rid of exhaust.
 
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