Getting knck sensor code at 35 miles, changed multiple times. original code was o2 sensor, then was cps(cranshaft position sensor) and now has been knock sensor code repeatedly. change it and drive for 35 miles and the idiot ligt comes on, same knock code. pulled wires and attached to a new knock sensor out of the truck and same issue.

SOURCE: obd code po200 and po300. 2002 chevy 2500 hd

this trucks have very coming problem with the injectors stuck open or close, and some times they just works great and some does not, dealer has an updated injector assembly, i recomend you to install this update and spark plugs and plug wires, if you had replace plugs and wires recently just redo the spark plugs with the injectors

SOURCE: O2 sensor problem

I have a 97 gmc sierra .This truck is the same as the chevy ok.Its a 350 5.7 liter 4x4 Z71.I took it to auto zone which was my first mistake.They put it the scanner and said bad O2 sensor.Ok so which one is it i said.They dont know.Well there four (4) O2 sensors in this truck i hope you know that.I had to replace all four of them before i had to take it to a real shop.It seems the fuel pump i replaced a week earlier with an auto zone fuel pump was bad.Ive changed my feul pump 4 times now and have 235000 miles on still running.You need to get your fuel pressure checked.It should be 65 psi to start it and 55 psi to run it.If the pressures are good it could be a different O2 sensor or maybe the mass air flow senor.My last option would be the fuel pressure regulator because it seems to be a waste of time and money.I would get that fuel pressue checked first.Good luck.

anwar alkhaldi

• 197 Answers
• Posted on Mar 14, 2009

SOURCE: 1998 Chevy s10 4 cylinder running rough

1- check there is spark come from spark wires
2- check the fire timing by looking for every wire in the right place
3- check there is injector signl
4- check for any vacuom leak
5- try to clean the MAF by brake and parts cleaner
6- try to reset all the code and see what will come after that

SOURCE: 97 Chevy Tahoe, bought used, not sure type Trans, diagnostic code

Number 5 cylinder may have clogged fuel injector. O2 sensor can be replaced on exhaust pipe. EGR valve can also be replaced. good luck

SOURCE: multiple cylinder misfire detected

Thank you for all the information. I don't see how you made it worse unless the injectors were not installed correctly. If you remove them you are suppose to replace the o-ring on each of them and oil them (the o-rings) before installing them. I would check the air filter and the CAT (for excessive back pressure. Also check the rest of the exhaust for damage. If a pipe is kinked or flattened it would need repair. Also GM's are known for some issues with there e-vap systems. You may want to check it out. The gas cap, charcoal canister, vacuum lines. Well good luck.