Rough Idle

**damac** · 05-23-2006, 11:31 AM

I have a 02 SS and when I start it in the morning the idle is real low 500 to 600 rpm and it rough. Sometimes it takes a minuet or more to even out and idle normal (850 rpm). Then after I drive it and take it out of gear the idle is low until I come to a complete stop then it will go back to normal. The only thing I can think of is the idle sensor is going out or maybe the MAS is dirty.

**MysticBowtie** · 05-24-2006, 04:58 AM

Ya, the IAC valve could be screwed up. Have you done a full tune-up (fuel filter, plugs, wires, etc)?

**damac** · 05-24-2006, 05:08 AM

I haven't done any type of tune up I only have 28,500 miles on it I didn't think I need to tune it up. What is the IAC valve? Is it common for the IAC valve to go out?

**SeVeReDiStOrTiOn** · 05-24-2006, 09:00 AM

Originally Posted by damac

I haven't done any type of tune up I only have 28,500 miles on it I didn't think I need to tune it up. What is the IAC valve? Is it common for the IAC valve to go out?

IAC (idle air control) valve is on the driverside of the throttle body above the TPS... it's the top sensor. It wouldn't hurt to take it out and spray it with some carb cleaner....cleaning the MAF filaments with some non-residue electrical cleaner wouldn't hurt either, it's the big sensor in front of the throttle body inbetween the bellow and the air lid. I'd also try replacing the pcv...it's only around $5-10. The pcv/hose is on the passenger side of the intake manifold towards the front and is inside the rubber tube that is skinny and then gets fat...it's inside the fat part. It's probably clogged from oil so you can either replace it or spray it with carb cleaner.

**MysticBowtie** · 05-24-2006, 09:02 AM

No, the IAC shouldn't have gone out, but you never know. I would change the fuel filter for sure, you'd be very surprised what one bad batch of gas could do to one of those. Also, I know you have low miles, but the car is about 4 years old. It could also be an O2 sensor. Any time my car has acted like that, it has been something with the ignition (plugs, wires, etc.) Do you still have the cats on the car?

**damac** · 05-24-2006, 09:42 AM

Yeah I still have the cats on their. I'm going to have to smog it this year so I don't want modify it too much. I'm think my BBK throttle body won't pass so I have to change that back pretty soon. (dam Cali. smog laws I hate them)

**SeVeReDiStOrTiOn** · 05-24-2006, 08:17 PM

Originally Posted by MysticBowtie

No, the IAC shouldn't have gone out, but you never know. I would change the fuel filter for sure, you'd be very surprised what one bad batch of gas could do to one of those. Also, I know you have low miles, but the car is about 4 years old. It could also be an O2 sensor. Any time my car has acted like that, it has been something with the ignition (plugs, wires, etc.) Do you still have the cats on the car?

A O2 will usually throw a code if it's completely bad or just not switching correctly...it might not in your 94 because it's a OBD I car. Also the o2's aren't used when in open loop...changing the fuel filter is a good idea though

The IAC doesn't have to be bad....like I stated it just might have built up gunk, I know mine did and the idle was more stable when I cleaned it.

But do what ya want damac...i'm just throwing out ideas anyway