Rough Idle HELP!

[02YukDenXL]

Short and long term fuel trims banks 1 & 2 at idle

 

[02YukDenXL]

O2 sensor voltages at idle. Both videos were taken after I drove for about 45 minutes this morning.

 

[#1taho]

It sounds like you covered all the basics. Beyond everything you checked and changed I would check the injector harness. I have had that problem not long ago. I did everything you did and found the harness by reading here. I would check the conector and tighten and spray contact cleaner then electrical grease. try again. if that don't work try moving the harness while the truck is running and see if anything changes. GOOD LUCK
please let us know what you find for future use.



FYI I did the tune up and coils also, cause it was due. did the coils too and one o2 sensor that was needed also. I was looking for a vacume leak and keeping in mind the harness problem. injector #1 had a broken wire, which gave me two missfire codes. I don't remember the cyilinders it told me. Sorry . hope some of this helps

 

[VikingTrad3r]

what sort of thing would cause a injector where to get broken?

 

[#1taho]

Dry wires, the heat from the engine, and vibration. the combination could cause the problem.
I don't know why it's only the injector harness but I have read it a few time. Could be the company that made the harness for GM used cheep materiel,haven't heard of any other harness problems. Just something to keep in mind.
I got a used harness from the wreckers and it fixed my issue.

 

[02YukDenXL]

Keep in mind I have had no codes this entire process.

 

[#1taho]

I missed that..... OOPS
Sorry about that.
Have you done a compression test? I am now grasping at straws now and just thinking of the basics.

 

[#1taho]

I am looking at your video's, not familiar with that scan tool. but the numbers should be the same. have you ever done any of the O2's? when you checked the cats was it hotter on the out side?

I don't look at the O2 sensors when diagnosing untill the last unless the code keeps comming back. Any little problem will affect the O2 readings on the scan tool ECT vacume leak,plug condition,fuel pressure. I wouldn't be concerned yet but keep an eye on the mv that it's producing. at your mileage they could be getting week. I don't think that's your problem but don't rule it out.
I wish I could be more help but I am out of ideas for you
There are alot of knowledgeable poeple here that maybe more help than I was.

 

[about20ninj45]

Im still pointing fingers at the idle control valve @02YukDenXL.

 

[VikingTrad3r]

i would go with iac / tps if it is only missing at idle.

he cleaned the tb but if these are really sealed iac units inside the tb then the iac can still be bad.

i dont know if miss is happening at idle only.