1997 chevy k1500 P0300

[Obs89]

I have a 97 chevy with brand new injectors and temp sensor,cap,rotor,plugs,plug wires. EGR valve. and new distributer, new fuel pump and filter. clean grounds. It seems to missfireing on 1 and 5 and it some time counts up on cylnder 2 but i believe it may be a false count. i have a new crank shaft position sensor but i didnt do a relearn. should i do that if so how. i need help. i am so confused on what the missfire is cause by. I will state it is some what new engine it has been fully rebuilt and built up. so i highly doubt its a intake gasket.

 

[Obs89]

I also forgot to mention that it’s only misfiring at idle.

 

[phantom 309]

I also forgot to mention that it’s only misfiring at idle.

What are your iac counts like? the vortec distributors can get worn and flop around a little at idle,. and check to see if your throttle blades are clean,.

 

[Obs89]

What are your iac counts like? the vortec distributors can get worn and flop around a little at idle,. and check to see if your throttle blades are clean,.

i beleive my iac stays at 36 at idle and my throttle body is clean. I cleaned it when i did my spider injectors.Also its a new cap and rotar also the distribor isnt to old maybe like 4 months .

 

[Obs89]

i have talked to another guy with same truck and built engine and he said if ur idle isnt set high enough the computer is going to think its misfiring. so i held rpm around 8-9 and misses went away so im going to with that. just letting everyone know that.

 

[Schurkey]

What is the commanded idle speed, and what is the actual idle speed? If there's a difference beyond about 10 RPM, you need to investigate why the computer can't control the idle speed appropriately.