Low idle problem....again...
06-03-2009, 04:51 PM
#1
Low idle problem....again...
Hi guys,
I've had this problem before and it turned out to be a disconnected breather hose, but no such luck this time.
I currently have a low idle when under load (in D, but in R is worse) ~4-500rpms.
So far I have done:
-Cleaned the IACV
-Changed spark plugs (didn't know if it was related or not but they needed to be done)
-Sprayed TB cleaner around to see if the idle jumped - nothing.
-Inspected for any obvious breaks in hoses/intake-nothing
-Checked for codes - nothing (even my KS is fine)
I have been getting craptacular gas mileage lately, and it seems (to my butt dyno
) that I don't have the same power/acceleration. This low idle started this winter when it got cold as **** here and I had to drive to work.
Something that may be of note here: When I start my car, the needle jumps up to around 1200, down to 450, and then back up to around 600 (in P) like it "swings" down. When I start my GF's car (97 Max), it doesn't do that, it just jumps up to 1200 and comes down slowly, like it should.
Any help as to what's causing this? Is my IACV fuxord? Does it sound like I have a vacuum leak? Exhaust leak? A case of teh car AIDS?
I've had this problem before and it turned out to be a disconnected breather hose, but no such luck this time.
I currently have a low idle when under load (in D, but in R is worse) ~4-500rpms.
So far I have done:
-Cleaned the IACV
-Changed spark plugs (didn't know if it was related or not but they needed to be done)
-Sprayed TB cleaner around to see if the idle jumped - nothing.
-Inspected for any obvious breaks in hoses/intake-nothing
-Checked for codes - nothing (even my KS is fine)
I have been getting craptacular gas mileage lately, and it seems (to my butt dyno
) that I don't have the same power/acceleration. This low idle started this winter when it got cold as **** here and I had to drive to work.Something that may be of note here: When I start my car, the needle jumps up to around 1200, down to 450, and then back up to around 600 (in P) like it "swings" down. When I start my GF's car (97 Max), it doesn't do that, it just jumps up to 1200 and comes down slowly, like it should.
Any help as to what's causing this? Is my IACV fuxord? Does it sound like I have a vacuum leak? Exhaust leak? A case of teh car AIDS?
Last edited by Coolsaber57; 06-03-2009 at 04:55 PM.
06-04-2009, 05:11 PM
#3
Senior Member
Join Date: Feb 2006
Location: Birmingham, AL
Posts: 1,066
Sounds like it could be a problem with the IACV but I would imagine it would throw a code if it was severe enough. Ive had problems with a low idle but mines only after it's hot when stopping. I would try replacing the IACV and see if it helps.
06-04-2009, 05:26 PM
#4
Any other ideas?
06-05-2009, 10:21 AM
#5
It could be one of the plungers in the IACV is sticking .... how well did you clean it? Did you take it all apart, remove everything and clean it, or just take it off, scrub and done? Could be a number of things unfourtunatly, got any codes? Are you running the stock IM - reason I ask is for relation to the EGR system. Did this come on all the suddun, or gradually? If sudden, when - what did you do prior to this problem starting?
Another though, when did you last run any injector cleaner thru the system? If you can run it directly into the IM, it's best, but if not, toss some junk in the tank and see if it helps. I'm not a firm believer that injector cleaner in a full tank does much good (not concentrated enough then IMHO) - when I do mine, I run it through a 1/2 a tank.
Another though, when did you last run any injector cleaner thru the system? If you can run it directly into the IM, it's best, but if not, toss some junk in the tank and see if it helps. I'm not a firm believer that injector cleaner in a full tank does much good (not concentrated enough then IMHO) - when I do mine, I run it through a 1/2 a tank.
06-05-2009, 05:42 PM
#6
It could be one of the plungers in the IACV is sticking .... how well did you clean it? Did you take it all apart, remove everything and clean it, or just take it off, scrub and done? Could be a number of things unfourtunatly, got any codes? Are you running the stock IM - reason I ask is for relation to the EGR system. Did this come on all the suddun, or gradually? If sudden, when - what did you do prior to this problem starting?
Another though, when did you last run any injector cleaner thru the system? If you can run it directly into the IM, it's best, but if not, toss some junk in the tank and see if it helps. I'm not a firm believer that injector cleaner in a full tank does much good (not concentrated enough then IMHO) - when I do mine, I run it through a 1/2 a tank.
Another though, when did you last run any injector cleaner thru the system? If you can run it directly into the IM, it's best, but if not, toss some junk in the tank and see if it helps. I'm not a firm believer that injector cleaner in a full tank does much good (not concentrated enough then IMHO) - when I do mine, I run it through a 1/2 a tank.
No codes or ghost codes
Stock IM
This happened over the winter when it was cold as sheit. I don't drive much during the week, so I can't pinpoint when it started happening....but it started this winter and has gradually gotten worse.
Where/how do you check the EGR? I've heard of it, but I'm not sure what it looks like (or what it's supposed to look like)
I'll try the injector cleaner, though i'm sorta with you on this, I don't really believe it does much more than put a tad bit more octane into the gas
If I were to get a vacuum gauge, how would I use it? Is there a specific hose I'd take off and see what vacuum it's pulling? Or would I have to do that hose by hose?
06-05-2009, 08:15 PM
#7
Huh ... well, the EGR first I guess. It's located behind the IACV, on the rear of the IM. If it gets clogged, it'll usually throw a code (but not always). To properly clean it requires a medium amount of work (have to remove the upper IM to do it 'right'). It's a block looking thing with a tube that goes down to the exahust and ties in. It gets carbon build up in it and some recommend actually just replacing the whole thing if it's bad enough. You can pop it loose of the IM easy enough and clean it a bit, but as I said, the whole tube gets gunked up and that's not 'easy' to clean.
For the injector cleaning, there is a canister you put the injector cleaner in and then it gets sucked straight into the IM and the injectors. You can use almost any vacuum line as long as it's got a decent vacuum. IIRC there is one on the side of the TB that is handy, been a while since i've done this so ....
Just for grins, you could check the CTS (coolant temp sens) and see if it's reading right. Does it seem to change at all if the car is warmed up or cold?
For the injector cleaning, there is a canister you put the injector cleaner in and then it gets sucked straight into the IM and the injectors. You can use almost any vacuum line as long as it's got a decent vacuum. IIRC there is one on the side of the TB that is handy, been a while since i've done this so ....
Just for grins, you could check the CTS (coolant temp sens) and see if it's reading right. Does it seem to change at all if the car is warmed up or cold?
06-05-2009, 09:35 PM
#8
Huh ... well, the EGR first I guess. It's located behind the IACV, on the rear of the IM. If it gets clogged, it'll usually throw a code (but not always). To properly clean it requires a medium amount of work (have to remove the upper IM to do it 'right'). It's a block looking thing with a tube that goes down to the exahust and ties in. It gets carbon build up in it and some recommend actually just replacing the whole thing if it's bad enough. You can pop it loose of the IM easy enough and clean it a bit, but as I said, the whole tube gets gunked up and that's not 'easy' to clean.
For the injector cleaning, there is a canister you put the injector cleaner in and then it gets sucked straight into the IM and the injectors. You can use almost any vacuum line as long as it's got a decent vacuum. IIRC there is one on the side of the TB that is handy, been a while since i've done this so ....
Just for grins, you could check the CTS (coolant temp sens) and see if it's reading right. Does it seem to change at all if the car is warmed up or cold?
For the injector cleaning, there is a canister you put the injector cleaner in and then it gets sucked straight into the IM and the injectors. You can use almost any vacuum line as long as it's got a decent vacuum. IIRC there is one on the side of the TB that is handy, been a while since i've done this so ....
Just for grins, you could check the CTS (coolant temp sens) and see if it's reading right. Does it seem to change at all if the car is warmed up or cold?
I get this feeling like it might be a vacuum leak, because of the power loss (seemingly) and gas mileage loss. I need to check more thoroughly for messed up hoses when I have time again. Are there any places where a vacuum leak could form but I can't see it from the top of the engine bay? It's all usually connected to the intake correct?
I'll check out the CTS, thanks!
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