99 3.0L - Rough IDLE at startup then clears within a minute

justinftw · #1 10-24-2012, 04:48 PM

I have read all the similar threads they seem a bit different than my issue. A little history: I recently replaced the dpfe sensor since it gave me a cel, the old hose kept coming off under open throttle conditions, replaced the hoses with some gas lines since that was the closest I could find at autozone, they are a bit smaller but went on ok. I replaced the fuel filter (prev owner replaced pump so he says, but he was a shady dude so who knows), replaced all the plugs/wires/coil pack.
However when the truck is cold it doesnt start very well and has a rough idle for about a minute. If I give it some gas it clears quicker. Once its warm it runs fine, no issues at all, and restarting it while its still warm is fine as well.

Suspecting: EGR valve, fuel injectors, fuel pump

Any suggestions on what to try next???

MossyOakD · #2 10-24-2012, 05:27 PM

Did you try cleaning your MAF sensor? Use MAF sensor cleaer only, is relatively cheap. If that doesn't do anything for you trying cleaning your IAC.

justinftw · #3 10-24-2012, 05:46 PM

Cool that sounds easy enough. I will test the resistance after cleaning to make sure the sensor is good. Do you know what the acceptable range is? I suppose if it doesn't work it could be either bad or not the culprit at all. Thanks for the suggestion, will let ya know how that goes.

MossyOakD · #4 10-24-2012, 05:49 PM

Quote:

Originally Posted by justinftw

Cool that sounds easy enough. I will test the resistance after cleaning to make sure the sensor is good. Do you know what the acceptable range is? I suppose if it doesn't work it could be either bad or not the culprit at all. Thanks for the suggestion, will let ya know how that goes.

Thats probably the culprit, a dirty MAF sensor can cause a lot of minor problems. My 1998 did the same thing yours is doing. After I cleaned it, it runs like a top now.

justinftw · #5 10-27-2012, 01:57 PM

Yes, this made a HUGE difference! Starts easily and no rough idle!! Thanks again MossyOakD

Compl3x1152 · #6 10-27-2012, 06:55 PM

Would the rough idle get worse when you gave it a little gas at first? My 3.0 does same thing on a cold start, but when I start to move a little it hesitates badly running very sluggish for around 5 seconds then it runs perfect.

justinftw · #7 10-27-2012, 07:13 PM

I would always wait till it settles down before taking off so I'm not sure about that. But the first couple gas hits in park would be rough. Bought a can of cleaner for like 8 bucks. That is always worth a try, can't do no harm.
But do make sure it's all dried out before you start it up.

Compl3x1152 · #8 10-27-2012, 07:21 PM

Worth a try, thanks!