Here's an interesting one. I have a 2000 Ls with the v8 with 155,000 on it. Today it starts giving me a weird idle issue. Here's how it went down and what has been done to the car recently. All fuel injectors/fuel rail were changed about 3 weeks ago and the car has been running great. No issues and a tad better gas mileage. Fast forward to today....I put in $20 worth of premium from a gas station that I regularly use. I drove about 2 miles and ended up behind one of those handicap vans but this van was giving off a crazy amount of diesel smoke. Enough so that I had to open the windows. I was behind the van for about a 1/2 mile. After passing it I drove at 60mph for about 3 miles and when I slowed to a stoplight the damn thing just shut down once at what is supposed to be normal idle. It started right back up and idled fine. I drove it about another mile and it did it again. No smoke, no odd sounds. Just barely an idle. Once I tapped the gas pedal it decided to idle and I drove it on in to work(14 miles) with a few spots where I felt it surge briefly but it ran. Here is where it gets weird, I leave work this evening and it starts up and runs great. But once it warmed up the idle issue presented itself again but only when I slow down for a stop sign or such. Anything below 2000rpm becomes an issue. If I blip the gas pedal the car regains it's idle and works fine. Idles perfectly in park and in reverse. One thing is for certain...I definitely can hear that car is stalling out as it is supposed to be coming down to normal idle. Any thoughts?
Idle/Stalling issue..I think
- Thread starter marcredd
- Start date
Quik LS
Dedicated LVC Member
well - funny day today with these issues....
but it sounds like a IAC valve or a vacuum issue.
the IAC - Idle Air Control valve - it is on the side of the throttlebody, it allows some air to 'sneak' past the throttleplate when the plate is closed. So when you are stopped - and foot off the gas - the car would stall because no air can get in - but the IAC has a little motor in it that continually adjusts (based on your idle rpm) to open a air bypass allowing air araound the throttleplate.
If it is stuck closed - you stall without having to keep you foot on the gas pedal a little - since no air gets in without opening the throttleplate.
if it is stuck open - you have a huge vacuum, leak and the car stalls no matter what you do with the throttle.
start with the IAC - if thats not the issue - then you may have a vacuum leak somewhere. The extra throttle help cover it up and keeps the egine running with more fuel to offset the un-metered air getting in from the leak.
but it sounds like a IAC valve or a vacuum issue.
the IAC - Idle Air Control valve - it is on the side of the throttlebody, it allows some air to 'sneak' past the throttleplate when the plate is closed. So when you are stopped - and foot off the gas - the car would stall because no air can get in - but the IAC has a little motor in it that continually adjusts (based on your idle rpm) to open a air bypass allowing air araound the throttleplate.
If it is stuck closed - you stall without having to keep you foot on the gas pedal a little - since no air gets in without opening the throttleplate.
if it is stuck open - you have a huge vacuum, leak and the car stalls no matter what you do with the throttle.
start with the IAC - if thats not the issue - then you may have a vacuum leak somewhere. The extra throttle help cover it up and keeps the egine running with more fuel to offset the un-metered air getting in from the leak.
Quik LS
Dedicated LVC Member
cool - make sure to check the under seat connector - before spending the $110 on the clockspring...
