91 c1500 stutter on acceleration

[badass66ss]

Sorry, also replaced TPS, muffler and cat. Thanks!
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[mountie]

Originally Posted by badass66ss

Sorry, also replaced TPS, muffler and cat. Thanks!
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This might be in left field, but I had a sort of stutter on a light acceleration when I had 25,000 miles on my '88 350 TBI. It was in the torque converter. The Lock Up was bad.

[ChevyTech]

You’re welcome and thank you for mentioning my posts to other member’s questions.

I agree it could be a transmission issue, if the shutter you refer to is not a misfire, but the first thing I would work on is the no cel light. The system should turn the service engine light on and store a trouble code if the oxygen senor is unplugged and the vehicle is driven.

The service engine light should also come on with the key turned on and engine not running.

If the light never comes on the bulb could be burnt or may have been removed by someone. Another possibility is that some of the power supply circuits to the ECM are not supplying power. Sometimes the ignition switch on the lower part of the steering column will fail and only supply power to some circuits coming out of it.

Here is a pin-out chart for testing the power leads to the ECM. This chart should be accurate for your 1991 350TBI truck.
http://www.wedgeparts.com/images/747ecm1.jpg

The chart above is from this site which has a lot of helpful information:
http://www.wedgeparts.com/t8tbi-4.html

Here is another chart that may help:
http://www.chevythunder.com/1227747_ecm_198892.htm

I would definitely get the service engine light working first.
If the light does work but the system will not set a trouble code I would pursue that.

[badass66ss]

Thank you both for your replies. I really don't believe this is a tranny issue as it is more of a misfire/fuel problem. The exhaust sort of pops and the new tail pipe is completely black inside after only 100 or so miles. I feel that it is possibly over fueling. The cel does come on when the ignition is turned on so the bulb is intact. I have a bad feeling ChevyTech is on to something, when I began looking through the wiring under the dash, they have a ton of wires spliced for an aftermarket alarm... Thanks for the chart, hopefully I will find time after work tonight to pull out my meter and start checking.
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