redseal97

how does it run under load?, do you notice any trailer hitching?, still sounds like a vaccum issue, sounds like you idle air control valve is trying to correct unmetered air since all other vaccum lines and brake booster hoes's where checked i only have a couple other possible causes, Intake or upper plenum gasket? PCV hose?, airfilter ductwork clamps or ductwork itself?

redseal97

scratch the intake gasket, i forgot you already had that done. one other thought though, your a/c system, how are the pressures? if when the a/c turns on and the pressures are to high causing a higher than normal load the computer will compensate with increased engine speed.

mayraliz76

The truck does run good nothing feels bad. How would I be able to check on the pressures of the A/C? It seems to run ok just the iddle jumps up and down when I'm at a stand still. So I will have to have them look at the upper plenum gasket, PCV hose, airfilter ductwork clamps or ductwork itself and tmaybe the pressure on A/C but I have to wait now until the Engine light comes on again. Thanks for your advice.

redseal97

check the clamps on the duct work yourself, just make sure they are tight, most common cause of a engine light after engine work, they just foret to get tighten,

mayraliz76

Thanks!

Rick's 06

When ever I read one of these threads it makes me wonder if the trouble codes you get really help diagnose your problem. Seems like you got the codes and started to correct what the codes were telling you to correct which seems like a reasonable plan, but you've been chasing your tail ever since. I wish I had some better advice for you cause I feel for ya. You've sunk in some serious money into it and still have the CEL with a jumpy tack. I does sound like a vacuum leak to me as well, but my advice and a token will get you on the subway. lol. Let us know if/when you find the smoking gun. Good luck.

redseal97

Ya the biggest poblem is a very high number of techs do not Know how to read the codes, usually if you get a lean/rich o2 code its NOT the o2, its something in the system affecting air/fuel Ratio, but to my disappointment most still just replace the O2 and think they are super tech....until the light comes on again, but it does sound like this garage has some faith in its tech if they are willing to guarantee for 90 days, i hope he gets it sorted soon, its problems like these that give all techs a bad name.

mayraliz76

So I took my truck to get a good engine clean. It looks awesome. And they told me I needed to get my seals replaced on the head valve gaskets because it was throwing a lot of oil....can this be causing my engine light to be turning on? And when the mech replaced the intake did he have to mess w/the head valve gaskets?

ted lafferty

thanks to ford forum advice i was able to pass inspection.

chavita28

So i just read through all the posts and my truck does the exact same thing. My CEL came on last month and took it to my mechanic and he said lets start simple first so he cleaned everything up and reset it. My light hadn't turned on till about a week after. I took it to get diagnosed and got the p0401 egr code and ignored it because mechanic said he checked it out and it was fine. Today I went to get it diagnosed somewhere else because I hate seeing the cel light on and now I'm getting the p0701 o2 sensor code as well. The place I got it diagnosed said it may possible be the fuel pump causing the o2 sensor to go off if it's getting to much or not enough fuel. But then what about the egr code. So I'm in the same boat as you man.