Its a 95 TA A4 and after it passes 4000 rpms, it sputters and will pop like a misfire sometimes and lose a lot of power. Other times it wont pop but just be really slow up to 6,000 when it shifts. It was a gradual problem and now got progressively worse. It used to clear out it seemed like after you beat it up a pass or two but now just stays around and sucks. So far I changed the optispark, spark plugs, MSD coil, and wires here and there that melted to the headers. I suppose it could be a fuel problem as well... I'm gonna change the fuel filter but am not sure if that would even cause this type of problem. Could a coil module cause this? Car runs great from idle to 4,000 with no miss or anything. Any suggestions as to what could cause this? Thanks very much for any help.

 

Check to make sure your IAT sensor is good Autozone can test it for you, and check your fuel pressure.

You could be getting false knock which would be causing your car to pull timing which would cause the loss of power and stumbling feeling.

I would suggest putting in the LT4 knock module and seeing if that doesn't clean things up for you.

- Z28WannaB

 

thanks... I have already installed the LT4 knock module a few months ago before the problem even existed. The IAT sensor I actually relocated into the rubber hose inlet by the fender for the CAI so the air actually is cooler and rewired everything. Would that sensor actually cause severe missing and lack of power? would igntion module do that? any other ideas what it could be? thanks guys

 

Contrary to popular belief, installing an LT4 KM into an OBDI PCM is a mistake. That sensor is programmed to monitor 2 knock sensors when you only have 1 and it is screwing up the spark signals on your 95 OBDI car. Someone assumed since the LT4 KM was a different part number, and it fit, that it would work in OBDI cars and it was "less sensitive". I disagree. A cheap and simple test would be to install a new, or the original LT1 KM.
GM did not make all these different knock sensors for nothing. The LT4 KM may work well in OBDII cars and it may even work temporarily in OBDI cars, but I fixed all my sputtering problems by reinstalling the proper LT1 KM.
16188309 Knock Module - LT1 95 Impala SS (2 knock sensors)
16217700 Knock Module - LT1 F-Body OBD-I (1 knock sensor)
16214661 Knock Module - LT1 F-body OBD-II
16214671 Knock Module - LT1 Corvette 97?? (2 knock sensors)
16214681 Knock Module - LT4 Corvette (2 knock sensors)
16214691 Knock Module - LT1 Impala 2
16188709 ??? (2 knock sensors)
16177690 Knock Module LT1 Corvette (94-95) (2 knock sensors)

OBDII Enhanced parameters
Knock Retard Degrees
Knock Sensor Active Counter Counts
Knock Sensor Activity Counts
Knock Sensor Minimun Learned Noise Volts
Knock Sensor Noise Channel Volts

 

just wanted to say the problem was finally solved. It turned out to be the ignition module. Thanks for all the help.

 

I put the LT4 out of my OBD II computer in my OBD I when i converted and i had bad stumbling past 4500. What sensor should i use for my car that is converted?

 

I would recommend the correct OBDI knock module for that computer. If it is an F-body OBDI then 16217700.