98 3.0 rough idle

[stampsc31757]

I need help with this problem as smog is coming up in a couple of weeks and need to get this sorted. It runs fine if the ecu has been reset. Once it has had time to read the sensors for about 15-20 miles it starts to have a rough idle. The idle air control valve, egr valve, dpfe sensor, egr solenoid, spark plugs, plug wires have all been replaced. I have looked for vacuum leaks and dont find any. I am running out of ideas. It only idles rough once it is warmed up. I dont know if it could be the coolant temp sensor. My gauge reads perfectly. Please help. I do not know where to take it next.

 

[monsterchuck]

Any codes? The check engine light does not need to be on for a code to be in the system. If you're disconnecting the battery to reset the PCM, you may have to drive it a few times to get anything to show up.

 

[stampsc31757]

I know you have to drive it around after you reset the ecu. It still has a rough idle. I dont have a vacuum leak unless its in the brake booster or an area like that. I still do not have any codes pulling up. Its been about 50-60 miles of both highway and city driving. No codes stored or pending. I just replaced the intake air temp sensor, fuel filter, and pcv valve. I haven't reset the ecu in a couple of days and i do get out and drive it around for about 15-20 miles a day to try to get the ecu to throw a code. It doesn't have any power loss, cold idle is great, normal driving is great. Just a very rough idle once it is warmed up. It does it stopped at stop signs while in drive or neutral, as well as in park. I haven't checked reverse or any of the other gears. I did put some fuel system cleaner in to see if that can clear it up. I also just put 91 in it to see if that helps any. Any help will be greatly appreciated.

 

[stampsc31757]

I found my problem. The vacuum line going from the valve to the solenoid was mixed up with another vacuum line.