I have an idle spike problem i have been combatting for 2 or so years. I have a 2004 v6. When i start it it jumps to 2600 rpm when warmed up and 2200 rpm when cold. The rpm's come back to normal quickly. Now i have replaced the lot, upper and lower inlet manifold gaskets, idle control unit, throttle position sensor, pvc valve, ALL vacuum hoses, maf sensor is working as it should be as is egr valve. With the new idle control valve the rpm symptoms got worse so i put the old one back on as i thought it was a contributing factor but it turns out it was not. I am at a loss as what to do next. It started right one time when it was sitting out in a heavy frost. The outside temp was minus 5. I put the scanner on it this morning and after running it for 2 or 3 seconds it told me the coolant temp was about 35c. I thought that was a bit odd so i will let her sit for a few hours and check the scanner again in regards to the temp. There are NO vacuum leaks what so ever. Any help with this greatly appreciated. Thanks.

 

I have since found a vacuum leak from the EGR valve as it enters the from the exhaust port to the inlet manifold and a leak is hence created. The egr valve is not seated correctly. I have also notice the Vacuum Solenoid valve does not work as well. It does not click on when powered and is jammed in the open position which in turn holds the diaphram and valve in the EGR valve permanently open and that in turn causes another vacuum leak. . Such fun are these Tributes.