Rough Idle When Warm

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Nov 19, 2005 | 02:26 PM

rosendosway

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Rough Idle When Warm

Okay so I'm having a problem figuring out what is wrong with my truck. I have a 98' expedition 5.4 engine. The truck started idling a little rough a few weeks ago and then the check engine light came on. Now it starts up beautifully and runs fine when its cold but as soon as the engine warms up it idles rough and dies at every stop light unless I put my foot on the gas to keep it on. We replaced the IAC valve and that didn't fix anything. I took it to autozone and they read the codes and it came out as P1071 and P1072. I'm not sure where to go from here. The guy at autozone told me to replace my fuel filter but I'm just not seeing that as my problem. Any suggestions?

Nov 19, 2005 | 07:30 PM

yardbird

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From: Foothills of NC

Have you tried cleaning the MAF sensor? It may be dirty, especially is you have a K&N filter. Also check for vacuum leaks.

Nov 20, 2005 | 11:11 AM

teacherubcl

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There's lots of talk on this site concerning the IAC valve...but this just happened to my 97 4.6 expy...turned out to be the O2 sensors on the drivers side. they'd finally wore out, so during idle and slow acceleration, there was hardly any fuel getting to the rail. I'm pretty sure I've read on this site those codes are o2 sensors.

I have a garage that I trust, and after diagnostics and repairs, 2.5 hrs labor (the o2 sensors are tough to get to, from what i've read on this site and others), the expy runs very well.

good luck