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Discussion Starter #1
I bought my 94 4.6 car almost a year ago and have been doing things to it slowly. I am to the point where i am going to start driving it an i am having some problems with it. At idle and a steady rpm it runs very smooth but during acceleration it has a miss. I got a bluetooth adapter and using the torque app on my phone i got the following data.
idle 940 rpm
maf 6.4 g/s
throttle 19.2%
ft1x1 0.0-3.1%
ft1x2 99.2%
ft2x1 0.0-3.1%
ft2x2 99.2%
O2 1x1 0.8-0.1v
O2 1x2 0.6v
O2 2x1 0.8-0.1v
O2 2x2 0.6v
fuel pressure 34# at idle 45# at wot
timing 25*
I am concerned by the second banks being maxed out and they never change. The plugs and wires have been replaced and the maf cleaned. I installed a bullitt intake and have not been able to find any vacuum leaks afterward which was my first thought. Its also not throwing any codes I am looking for some insight as to where i should go from here, i am hoping its not a bad computer.
When i first got it i modified the maf housing like in the tech article and found out later that that was not good idea. I got another housing from the junkyard to replace it and the readings where the same with both housings so i dont know if the maf sensor could be bad also.
Thanks.
 

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I bought my 94 4.6 car almost a year ago and have been doing things to it slowly. I am to the point where i am going to start driving it an i am having some problems with it. At idle and a steady rpm it runs very smooth but during acceleration it has a miss. I got a bluetooth adapter and using the torque app on my phone i got the following data.
idle 940 rpm
maf 6.4 g/s
throttle 19.2%
ft1x1 0.0-3.1%
ft1x2 99.2%
ft2x1 0.0-3.1%
ft2x2 99.2%
O2 1x1 0.8-0.1v
O2 1x2 0.6v
O2 2x1 0.8-0.1v
O2 2x2 0.6v
fuel pressure 34# at idle 45# at wot
timing 25*
I am concerned by the second banks being maxed out and they never change. The plugs and wires have been replaced and the maf cleaned. I installed a bullitt intake and have not been able to find any vacuum leaks afterward which was my first thought. Its also not throwing any codes I am looking for some insight as to where i should go from here, i am hoping its not a bad computer.
When i first got it i modified the maf housing like in the tech article and found out later that that was not good idea. I got another housing from the junkyard to replace it and the readings where the same with both housings so i dont know if the maf sensor could be bad also.
Thanks.
i had this issue on my 94 4.6 cougar... it would stumble during load... problem was the plastic airbox ontop of the engine... there is a seam where both halves are joined, it Cracks there. The air is then sucked in after the MAF sensor causing a Lean condition and causing a miss/hesitation. remove it and check it out.
 

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i had this issue on my 94 4.6 cougar... it would stumble during load... problem was the plastic airbox ontop of the engine... there is a seam where both halves are joined, it Cracks there. The air is then sucked in after the MAF sensor causing a Lean condition and causing a miss/hesitation. remove it and check it out.
He has a bullitt intake so none of that applies.

You likely have an intake gasket leak, exhaust leak, or O2 sensor problem as a last resort. First thing is to pull the plug wires and check for coolant/oil in the wells because misfires can cause heaps of trouble that are disguised as fueling issues. Then pull the plugs and inspect them individually.
 

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Discussion Starter #4
Well I was messing around with the car today and realized the hesitation was gone, after looking around I had forgot to reinstall the air filter. Apparently its clogged just enough to affect it during acceleration. I am still having fuel trim issues so I started checking everything again and think my upper plenum gasket might be bad so I ordered a new one. So well see If that helps anything when I get it put back together. I used felpro gaskets when I did the intake and have heard of some people having issues. What is it about them that are prone to failure? Mine lined up well and gave me no indication that they wouldn't work. I am going to see if the Plenum gasket was the culprit before I tear it down any further.
I was wondering could a clogged cat cause any of these issues? A friend of mine was chasing a weird drivability issue with his car and it ended up being that.
Thanks for the input.
 
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