I have this rough idle issue when idling and it goes away after revving past 1500 rpm. Whether it’s in gear or not, it makes no difference. There is no issue starting the truck, but the idle is progressively worse as it warms up. I have replaced plugs and wires, fuel filter, HVAC vacuum lines (near brake booster and HVAC reservoir ball), cleaned out throttle body and EGR valve, and it drives noticeably better. However it still rough idles the exact same. I have browsed other forums and YouTube about other vacuum lines which I cannot find. One thing to mention, there is a slight whistle sound coming from the passenger side of the engine somewhere behind the alternator which I never heard, and was birthed after replacing HVAC vacuum lines.

 

Any codes?

what are your fuel trims at idle and 2500?

Do you have a recent compression test?

George

 

George, I appreciate the reply. I will post a video link of starting, driving, WOT test, and rev test on the truck. Fuel trims are on the video during all of this, and I will run a compression test when I get more time. No codes and no engine lights.

 

I just need your 4 fuel trim values in park at idle and again at 2500 rpm. No drive is necessary.

George

 

ok NP here is the fuel trims as requested

 

I just wanted the four numbers, I cant read the scanner screen in these videos. I yield this thread to someone with better eye sight and patience than me. It looks like either the scanner is having problems, the class 2 data lines are dropping out or the ECM has issues (rare). Good luck, there are other capable people here than can help.

George

 

thanks