Idle problems

[97sprt4x4]

i can't figure out if any of the search stuff that comes up applies to this. but recently, the check engine light has come on. and at idle the rpms surge from around 800-400 back to 8000 and it's a really bad idle.. i don't know what it could be, MAF? IAC?

Justin

 

[BrooklynBay]

Do you have any code numbers? It might be a vacuum leak.

 

[97sprt4x4]

no i don't have a code puller, and i'm not sure how to get them myself.

 

[BrooklynBay]

Go to Autozone to have the codes read for free.

 

[98sohcxlt]

try some sea foam, also make sure your pulleys and serpentine belt are in good condition and pick up some pully spray. that may not solve your issue, but thats what i did and it seems to have worked

 

[TheXMan007]

I had the same problem a couple of years ago on my 98 Sport. The dealer told me it was the upper and lower intake manifold gaskets. They quoted me 700 to replace them. The parts cost 12 dollars and it took me an hour and a half. I haven't had an idle problem since.

 

[trj360]

Do you have a hard time keeping it running for a minute after it was started? I had that problem, plus your symptoms, and it was the idle air control valve.

 

[gijoecam]

The IAC and the lower intake manifold gaskets are the most common causes of that problem. $75 and a Sunday afternoon will likely fix it.

-Joe

 

[97sprt4x4]

i'm going to go the root of seafoam, clean IAC, Clean Maf, then i'll replace the gasket if the problem still persists, I'm at college so when i go home i really don't have all that much time to work on my ex. so i'm doing things in order of most time consuming in total. But thanks for all the advice

Justin

 

[gijoecam]

Seafoam won't fix an idle problem... It'll just create a bunch of smoke. I wouldn't waste my time...

The IAC, while it *can* cause it, generally either works or it doesn't. If it'll idle at all, it's probably not the IAC. I wouldn't waste my money there either.

More often than not, it's either a vacuum leak due to a cracked or missing hose, or the lower intake manifold gaskets. It's getting more and more common as this generation of engines ages. Just a trend I've noticed on this board for nearly a decade...

 

[97sprt4x4]

well on the intake i got from ebay and had to custom fab to work, the black hose, which i'm assuming is a vaccum line, didn't quite fit, it was too long, so i had to scrunch it back so it would fit in the hole, and it's not air tight.. would that cause the problem???

 

[gijoecam]

If it's leaking, possibly... Un-metered air flowing into the intake downstream of the MAF can cause all kinds of issues. However, mine somehow became disconnected after my last oil change (popped out of the valve cover) and was like that for a couple weeks until I happened to be checking the oil while getting gas. It never missed a beat.

 

[97sprt4x4]

alright, thanks joe, i'm going home this weekend, i'll check that hose and sea foam it, it may not need the foam, but it won't hurt seeing as i've got 100000 miles on it.

Justin

 

[aldive]

i can't figure out if any of the search stuff that comes up applies to this. but recently, the check engine light has come on. and at idle the rpms surge from around 800-400 back to 8000 and it's a really bad idle.. i don't know what it could be, MAF? IAC?

Justin

Take a look at http://www.explorerforum.com/forums/showthread.php?t=169335&highlight=quest

 

[97sprt4x4]

thanks al, but it's not a rough idle, it feels like it's stalling it's happened before and it was the O2 sensors, and the maf but i can't belive it would be this soon again because it's only been 20000 miles..