# 1996 Chevy K1500 5.7 350 rough idle 231,000 miles



## hknow2 (Aug 17, 2009)

I recently purchased this vehicle. The vehicle was running decent, so I decided to tune it up. I replaced the Plugs (Bosch Platinum), Wires (Bosch), and Cap/rotor (Duralast). After replacing these items I noticed that the vehicle had a consistent skip and rough idle almost 2 seconds apart. There isn't any rough accelaration or any hesitation when I acel. Only when sitting idle it seems to have some sort of misfire. I used a OBD code reader and it did show that the MAF (Mass Air Flow sensor) was out of range, and Oxygen Sensors were out of range, misfire on cylinder one. I cleaned the MAF, changed out the new wire on plug one with the old wire, and cleared the codes. I did clear all the codes and none returned except the oxygen sensors, but still had rough idle. I changed plug one with the old one and still had rough idle. I replaced the new plug and wire back, and changed the Distributor Cap and Rotor with an Accel Gold Distributor Cap and Rotor. This did not make any differences, I then changed the Ignition Control Module, but no changed either. I am not getting any other codes on the reader except P0430 and P0420 and P0430. I don't know what else to replace or check, any new ideas?


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## emilio garcia (Apr 14, 2008)

sounds like one of your injectors is bad i would not try to clean it . find out what cly is it and replace with a new one. been there with my silverado let me know and good luck


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## hknow2 (Aug 17, 2009)

I don't have injectors.


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## moorejav (Sep 16, 2009)

I have the exact same problem. 1995 GMC Sierra 5.7L 4x4. I changed out the Cap, rotor, plugs and wires, and now it has a random missfire when it idols. I still have plenty of power, and I only notice it when its in idle.

Did you use AC Delco parts... cap, rotor etc.?

I have tried two different sets of caps, rotors and plugs. Bought one set at autozone and one set at checker. Still didn't fix it. 

I have thought about putting on AC Delco parts, cause some guys say they can be picky.

Let me know if you have had any luck.


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## moorejav (Sep 16, 2009)

Also, if you did find a solution please share... 

This is driving me insane!

Thanks, and if I find a solution I will let you know.


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## octaneman (May 13, 2009)

Hi hknow2

The codes you posted confirm that the oxygen sensor is not functioning properly and it needs to be tested, also check your exhaust for any leaks. Judging from the codes, the hesitation problem is most likely coming from a blocked catalytic converter, have the emission system tested.

post back your findings.


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