Rough Idle Cold Start Moisture?

Alwick · Post by **Alwick** » 02 Nov 2012, 06:45

My '98 V70 GLT w/115k has developed an annoying habit of an occasional rough idle on cold starts. I'm thinking that it's moisture related because I think that every time it's happened has been after sitting for an extended period after torrential rain, like the hurricane we had this week.
It fires up, but the idle is very rough, almost a rumbling/chugging sound with excessive vibration for about 15-20 seconds, after which time it smoothes out and runs fine. There is no CEL.
Plugs, wires, caps are all less than one year old and are OEM. Battery is also only one year old.
Thoughts? Anything specific that I can check?

Post by **rspi** » 02 Nov 2012, 07:33

Could be a number of things. Low fuel pressure at start, vacuum leak, IAC valve sticking, coolant temp sensor going bad, etc. You'll have to have it trouble shot.

Alwick · Post by **Alwick** » 02 Nov 2012, 07:53

Well, temp sensor is a couple years old, and OEM. IAC has been cleaned.
Wouldn't a vacum leak manifest itself more when the car is hot and hoses have expanded?
This happened last summer too, after a huge rain. I changed the caps and wires and it hasn't happned agin until now. I am hoping it is water related.

Post by **jblackburn** » 02 Nov 2012, 07:55

Check that the hood seal is intact between the windshield and hood. I had a tear in it, and it would leak down directly on the cam sensor/spark plug area and cause a hard start sometimes after a hard rain.

Alwick · Post by **Alwick** » 02 Nov 2012, 07:57

Yeah, I will do that when I get home. It rained like a b***h here on Monday and Tuesday (Sandy - luckily not as bad as in NY).