Rough Idle....sometimes.

[SHOspazz92]

This would be for Ashley's 3.2 MTX. The car has recently had a Top 60k done, as well has a new CID and new 02 Sensors. It get's great gas Mileage and has plenty of power and does not leak a drop.

Here's the issue. At times when you start her car the idle can get pretty rough and low. Usually, if you put some load on the engine or maybe a few blips of the throttle it will clear up, sometimes it maybe take a little more. It is not a weather dependent issue, it does not matter if the car is already warmed up or being started for the first time and it does not happen all the time.

The car will not throw a CEL and there are no codes. I've searched the Forum but a lot of the issues did not really match mine.

What do you guy's think?

-Sam

 

[Bob Gervais]

Did it do all of this before the 60k?

 

[LOUDSHO92]

The IAB might be on its way out. Try cleaning it first.

 

[SHOspazz92]

Did it do all of this before the 60k?

Yes it did. It did this even after the Cam Sensor was replaced, Tho the Cam sensor was causing all kinds of cool issues by itself.

-Sam

 

[nothingtoseehere]

May be time to part it out ... if anyone wants the parts :laugh_ti:

 

[platoribs]

I'll give ya $500, but you gots to take it all apart and package it in boxes so it'll fit in my garage.

 

[sperold]

If the car has an idle air control valve, I would look at it first.
Next would be the throttle position sensor.

 

[Bob Gervais]

As mentioned, clean/inspect/replace IAB. Sounds to me like an intermittently sticky IAB.

 

[frosho]

Has Bab been near the gas tank recently?

[rimshot]

The first thing I'd suggest is cleaning the MAF and the IAC valve (as mentioned).

 

[Bob Gervais]

Filler neck circumcisions hurt like a motherf*cker.

 

[St Louis SHO]

I'd pull a plug and see what it looks like (unless replaced recently) Other than that, you can do what was mentioned above, clean the IAC.


It also could have a sticking injector. Try running some good injector cleaner through it (seafoam or lucas)


- James

 

[itwonder]

I'd take the idle air control off and clean it. Then do the reset procedure.

 

[SHOtimer]

...our '01 SLO was doing this. Turned out to be the fuel pump on it's way out. When it first turned on - it would provide low fuel pressure and the motor would struggle.

Have you tested your fuel pressure?

Doug

 

[SHOspazz92]

...our '01 SLO was doing this. Turned out to be the fuel pump on it's way out. When it first turned on - it would provide low fuel pressure and the motor would struggle.

Have you tested your fuel pressure?

Doug

No, but this thought has ran through my mind. (Actually, Ashley suggested it). I sure hope that's not the case.

-Sam

 

[SHOstopper1992]

Mine does the exact same thing... Plus if I try to leave when doing this it stalls going up the street...

 

[rubydist]

the fuel pump has a little check valve in it to keep the fuel pressure up when the pump is off - if this check valve leaks, you can get the symptoms described. you can test for this by turning the key on for a few seconds, then off, then on again several times before you start the car. if that eliminates the symptoms, then that suggests that the fp check valve is leaking. this has nothing to do with the actual performance of the pump, it just makes startups unpredictable.

 

[SHOspazz92]

the fuel pump has a little check valve in it to keep the fuel pressure up when the pump is off - if this check valve leaks, you can get the symptoms described. you can test for this by turning the key on for a few seconds, then off, then on again several times before you start the car. if that eliminates the symptoms, then that suggests that the fp check valve is leaking. this has nothing to do with the actual performance of the pump, it just makes startups unpredictable.

Since the car does not start up roughly every time, this might be pretty hard to narrow down with this test. I'll try however.

Also, If the fuel pump is starting to go on this car, Will Fuel pressure be lower then normal under all conditions? I ask because I want to see what kind of fuel pressure this car is getting.

-Sam

 

[SHOspazz92]

This is not new, but came to mind just now.

Sometimes the Fuel pump on this car is VERY Loud. If I'm standing at the front of the car while the engine is running I can clearly hear the Fuel Pump running. I'm going to assume this is not normal. And, It does not do this all the time, of course.

I'm going to check/clean the IAC first of course...but if that does not cure it...well them I'm hoping (Not really that solves it).

-Sam