idles rough

[00GTpony]

My idle has been rough, the plugs are farley new... what else could it be, i no it could b coil packs but wanna check everything else out before i spend 300 on coil packs. just hit 70,000 miles

 

[00GTpony]

pcv valve?.. iac?..dirty air filter ( i dont think that can cause that )

 

[32ValveRom]

I had to clean my iac valve because I was idling high. When's the last time you had a tune-up?

 

[Kilgore Trout]

Could be any one of a million things. You will have to provide more information and/or do some inspection and maint under the hood.

 

[00GTpony]

the only tune up was plugs about 20,000 miles ago, air filter i dont no when it was changed last, and the coils, pcv valve have never been changed... fuel filter about 20,000 miles ago to. i probably could use a change on that for i run it low on gas alot.

ill try cleaning my iac but my idle doesnt go high its just intermitenly rough.

 

[1fun281]

the only tune up was plugs about 20,000 miles ago, air filter i dont no when it was changed last, and the coils, pcv valve have never been changed... fuel filter about 20,000 miles ago to. i probably could use a change on that for i run it low on gas alot.

ill try cleaning my iac but my idle doesnt go high its just intermitenly rough.

Stupid question but are you leaking coolant or anything like that?

 

[302GTS]

Stupid question but are you leaking coolant or anything like that?

No such thing as a stupid question, brother!

Like he said, OP, are you leaking coolant, and have you checked out oil? It's obviously a long shot, but head gasket failure can always be a culprit. As for any other things other than a basic tune-up, I can't really help out as my 5.0 is a bit different than you crazy modular guys' motors.

 

[1fun281]

No such thing as a stupid question, brother!

Like he said, OP, are you leaking coolant, and have you checked out oil? It's obviously a long shot, but head gasket failure can always be a culprit. As for any other things other than a basic tune-up, I can't really help out as my 5.0 is a bit different than you crazy modular guys' motors.

Thanks
Only reason i ask is because i have been having problems with my car at an idle too, and i have been leaking coolant but no puddles have been showing. We narrowed it down to im most likely loosing coolant through a intake gasket leak somewhere and im probably burning it up.

 

[00GTpony]

just went outside and checked is there is just about no coolent left in the resavare. so i guess that means the head gaskets leaking?.. or mayb its leaking out of the mainifold?

oil looks fine.

 

[00GTpony]

also ive had this intermitent rough idle for like 8 months, and just noticed now the the coolant is just about empty. so it took 8 months to drain.

 

[wmburns]

Pressure test coolant system

How about starting by blowing out the spark plug holes with compressed air? Look for moisture in the holes. Look for evidence of coolant leakage. Clean.

Remember that moisture may cause the spark to ground out and this can damage the insulating boot. It is possible to buy replacement boots.

Refill the coolant to the full cold level. This will give you a known starting location.

If you need piece of mind and need to know right away, perform a coolant pressure test. Autoparts stores will rent the tool for the DIYer.