Topic Options
Rate This Topic
#219040 - 03/09/13 09:37 AM Idling Problems now?
snowcrash Offline
Member
Registered: 05/05/03
Posts: 868
Loc: charlotte, nc
The car has started to run rough, it didn't do it as bad until I changed out the boost actuator and boost solenoid but I guess by fixing that problem, it made it idle worse.

Anyways, it sounds like it has a miss to it maybe and just doesn't idle right, it is idling up and down from 700 - 1100. If you pouch the gas pedal and let off, it'll drop down almost to where it will act like it is going to cut off. At night the lights will dim way down when it does this.

The MAF went bad last year sometime, so I got a replacement from Advance, a BWD. Well, after fixing the actuator and solenoid, I said that maybe the MAF is bad. You could unplug it and the car would run better but it hadn't thrown a light yet.

I took it back the other day and got another one. That one stayed in the car for 2 days because it was terrible and made the light come on. The first time, the light came on because I was running the car without it. When I cleared the codes though, it said the MAF code and a random misfire code.

I put the third MAF in and the car does seem to run good like it did with the first MAF, but still idles horrbile.

What could it be, you still think the MAF is the issue if you can unplug it and it runs better.

Or could it be the Idle control valve or throttle position sensor. I replaced the idle control valve back in 2011, it had a one year warranty, so my luck it could be bad.

I'm almost tempted to buy a original used MAF and try it but I just don't know.

I did test the coil packs and they are all working properly. The car runs great as long as you are not idling. Haven't had a chance to hook up to see what the light is on for but I'll check that out later today.

If there is still anybody on the board that can help, I need it?
_________________________
charlie
black 98 gtp sedan, 222,000 and running great with the new used tranny! laugh
zzp 3" d/p aluminized
dhp 1.0
Top
#219041 - 03/09/13 02:53 PM Re: Idling Problems now? [Re: snowcrash]
Blackarrow98GP Offline
Member
Registered: 06/29/06
Posts: 3618
Loc: CT, U.S.A
Before buying more parts, check it over for vacuum leaks. If your EGR valve is hooked up, check the tube that connects it to the intake manifold, could be cracked.
Top
#219042 - 03/10/13 10:35 PM Re: Idling Problems now? [Re: snowcrash]
snowcrash Offline
Member
Registered: 05/05/03
Posts: 868
Loc: charlotte, nc
Yes, I do have the EGR valve hooked up. Is there any real way to check the pipe for leaks or just feel for air coming out of it? Almost positive that the vacuum lines are ok, most of them and the connectors were replaced when we did the LIM a few years ago. From looking them and checking fit, they seem good.

Also, you're talking about the metal tube coming from the EGR to the intake?

Thanks


Edited by snowcrash (03/10/13 10:36 PM)
_________________________
charlie
black 98 gtp sedan, 222,000 and running great with the new used tranny! laugh
zzp 3" d/p aluminized
dhp 1.0
Top
#219047 - 03/16/13 03:21 PM Re: Idling Problems now? [Re: snowcrash]
RooK Offline
Member
Registered: 03/07/05
Posts: 5158
Loc: Southern KY
The EGR itself can get carbon in it and keep it open, as well as the electrical part failing to close it.

Definitely sounds like a vacuum leak (egr valve opened at idle would be one too). Check the T under the snout, it's bad for doing it. Don't forget the elbow on the throttle bodies and map sensor (this is kinda hidden).
_________________________
'13 Mustang 3.7V6 - MT82
'00 GP SE (L67 Swap, XP, Headers, 3.25")
'98 GTP, '01 Bonne
Top
#219048 - 03/18/13 11:57 AM Re: Idling Problems now? [Re: snowcrash]
snowcrash Offline
Member
Registered: 05/05/03
Posts: 868
Loc: charlotte, nc
Thanks Rook,

So there are some hidden vacuum lines going to that map sensor and to be sure, it is located on the backside(firewall) of the motor above the valve cover area?

I'm pretty sure the T under the snout is fine because we had to make our on T when we did the LIM a few years ago and some of those connections broke. I'll check everything out though for sure.

I'm still leaning toward a maybe a Idle sensor because if I remember correctly, it never would throw a SES light when the last Idle sensor went bad until right before changing it out.

I just don't see how 3 MAF's from Advance could all be bad because the 1st and 3rd ones have the car running the same, the 2nd one I have tried maybe was bad.

I ran some Seafoam through the booster line to clean any carbon out the other day just to check that one off the list and also put some in the gas so I should be good to go on that part.

Either vacuum or electrical?
_________________________
charlie
black 98 gtp sedan, 222,000 and running great with the new used tranny! laugh
zzp 3" d/p aluminized
dhp 1.0
Top
#219049 - 03/19/13 12:47 AM Re: Idling Problems now? [Re: snowcrash]
RooK Offline
Member
Registered: 03/07/05
Posts: 5158
Loc: Southern KY
Yeah, it's on the back side of the M90, mounted upside down. The vacuum line from the T under the snout routes to it.

Seafoam will clean carbon from the intake/valves/cylinders but not the EGR. Only thing you can do there is manually remove it. It's hooked directly to the exhaust and on older cars, built up chunks of carbon from the exhaust break loose and just get lodged in there.

IACs can go bad, but it's rare. Might try removing it and cleaning it and the hole it sets in, along with the throttle plate. It can't hurt. Carb cleaner and a toothbrush is all it takes.

I'm about to start diving back into the GTP game with my '98 I've had sitting for the past year. So, I may be popping around from time to time.
_________________________
'13 Mustang 3.7V6 - MT82
'00 GP SE (L67 Swap, XP, Headers, 3.25")
'98 GTP, '01 Bonne
Top
#219050 - 03/20/13 10:04 PM Re: Idling Problems now? [Re: snowcrash]
snowcrash Offline
Member
Registered: 05/05/03
Posts: 868
Loc: charlotte, nc
Is that the one you couldn't get a title for?

Well here is an update, I checked that fitting and it seemed good. I checked all of the vacuum lines and they all seemed good.

I can unhook the MAF connector and the thing will run great. It doesn't fluctuate in idle and drives good but if I have it hooked up, it sounds like it has a cam and the idle is up and down.

I sprayed carb cleaner though around all all the vacuum lines and fittings to see if anything changed and it really didn't, but it did when I sprayed it around the injectors or intake.

When sprayed on the injectors or around the injectors, the car would run different for a few seconds if you sprayed enough. Not sure if it was sucking sound or like a boiling sound but it did sound like it was doing something when I would spray the stuff around the injectors or I guess the intake area. It did it the worse I guess around the #6 injector, back side, closest to driver's wheel.

Don't really know what that means but it seems like it idled fine up to when I started messing with the boost actuator and solenoid.

Do you think the MAF is just bad and causing it to run bad. I checked the codes and it is still saying Mass Air flow or Air flow low circuit or something reading and random misfire. I'm sure the misfire is from the car not wanting to idle right. I really do not want to have to pull the s/c and intake again since the car is not leaking or burning coolant like it was when we did the LIM.
_________________________
charlie
black 98 gtp sedan, 222,000 and running great with the new used tranny! laugh
zzp 3" d/p aluminized
dhp 1.0
Top
#219059 - 03/28/13 05:53 PM Re: Idling Problems now? [Re: snowcrash]
RooK Offline
Member
Registered: 03/07/05
Posts: 5158
Loc: Southern KY
Well, the idle shouldn't be changing from spraying around the injector regardless. Something is going on there. Did you replace with metal or plastic intake gaskets? Replace injector o-rings at the same time?

Unfortunately the MAF code you're getting is a catch all. It can mean the MAF is messed up, or... vacuum leaks, unmetered air entering the engine, all that good stuff. Only way to know would be to watch the MAF and see how it reads as the car runs. However, unplugging it and the car running good is a sign of a bad MAF.

Yeah, the '98 is that one. However, I managed to get a salvage title for it. It's even insured and road legal atm, it just has some issues I need to work on and a bad vibration I've got to fix in the front end.
_________________________
'13 Mustang 3.7V6 - MT82
'00 GP SE (L67 Swap, XP, Headers, 3.25")
'98 GTP, '01 Bonne
Top
#219060 - 03/29/13 12:21 AM Re: Idling Problems now? [Re: snowcrash]
snowcrash Offline
Member
Registered: 05/05/03
Posts: 868
Loc: charlotte, nc
That's good about getting a title for it. We just went through somethings trying to get some of our trailers tagged but the titles were all screwed up.

About the car, I replaced the MAF with another one from Advance but this time I put a Cardone rather than a BWD. The car seems to be a litte better but still idles terrible at idle.

I'm guessing if the intake is sucking air, that would cause it to have a rough idle? When spraying the carb cleaner around it, I guess it's just sucking it in and making the motor run different as long as you don't spray too much.

When we did the LIM, yes we used the GM aluminum gaskets and put new o-rings on the injectors.

Just wondering, if the o-rings were bad on the injectors, would that cause it suck air and act as if it has a intake leak? I just don't see how the intake would be sucking air or be bad if it was done right by the instuctions as we followed.

I guess I could always get some o-rings and change that first before doing the intake?

Also, I check all the vacuum lines and didn't find anything wrong. Even the one on the back side seemed fine. I did mess it up some when I pulled it off to look at it, but for the time being, I taped it up real good and fixed it for now. The car didn't run any worse so I figured I'd wait and fix it when I decided to do it.
_________________________
charlie
black 98 gtp sedan, 222,000 and running great with the new used tranny! laugh
zzp 3" d/p aluminized
dhp 1.0
Top
#219076 - 04/23/13 11:03 AM Re: Idling Problems now? [Re: snowcrash]
20gtp02 Offline
Member
Registered: 04/13/06
Posts: 6709
Did you replace TPS yet?
I had this issue on and off for almost a year.
Car would be fine for months, then start acting up.
Mine would like to idle 1500-2000 by itself.
I could do 40 mph without putting my foot on the pedal.
I finally bought a new TPS after getting annoyed.
That fixed my idle issue.
_________________________

2002
Top
#219078 - 04/23/13 11:08 AM Re: Idling Problems now? [Re: 20gtp02]
snowcrash Offline
Member
Registered: 05/05/03
Posts: 868
Loc: charlotte, nc
Originally Posted By: 20gtp02
Did you replace TPS yet?
I had this issue on and off for almost a year.
Car would be fine for months, then start acting up.
Mine would like to idle 1500-2000 by itself.
I could do 40 mph without putting my foot on the pedal.
I finally bought a new TPS after getting annoyed.
That fixed my idle issue.


I should have updated this thread to, but I was able to fix my idling issue. Turns out the injector O-rings were bad and allowing it to suck air. I knew it was something to do with them or the intake gasket. Luckily, I narrowed it down to them by taking some carb cleaner and spraying directly over/on the O-rings which made the engine change idle.

Doing the O-rings first also was the easiest thing to do and the parts and shipping from Rockauto was only like $6 I think.
_________________________
charlie
black 98 gtp sedan, 222,000 and running great with the new used tranny! laugh
zzp 3" d/p aluminized
dhp 1.0
Top
#219079 - 04/23/13 11:10 AM Re: Idling Problems now? [Re: snowcrash]
20gtp02 Offline
Member
Registered: 04/13/06
Posts: 6709
That'll do it.
Most fixes are easy on the GP. Just figuring them out
is the hard part.
_________________________

2002
Top