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GM Bob
GM Bob, ASE Certified Technician
Category: Pontiac
Satisfied Customers: 1129
Experience:  30 plus years. experience as GM technician, ASE Master Technician and GM Certified.
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2004 Pontiac grand prix gtp stalls when taking off,does not

Customer Question

2004 Pontiac grand prix gtp stalls when taking off,does not do it in reverse
Submitted: 2 years ago.
Category: Pontiac
Expert:  AZTechBrian replied 2 years ago.

Does it start running bad? or just instantly dies? like the key was turned off

Customer: replied 2 years ago.
no,runs and idles fine,just will not run forward,stalls and cuts off,does not d it in reverse
Expert:  AZTechBrian replied 2 years ago.

OK. Do you have any DTCs? I assume that your 0135 was remedied with the o2 sensor replacement?

Customer: replied 2 years ago.
only dtc is a u1000..the car will rev up fine in park or netural,0135 went away when I replaced the bank 1 sensor 1 oxygen sensor,i can foot brake the car and make it stall or take off,but it will no do it in reverse
Customer: replied 2 years ago.
fuel pressur is 55 psi and never drops when stalling or chuts off
Customer: replied 2 years ago.
the electronic throttle blades are showing 8 degrees of angle at idle,it goes to 100 as its suppose to full throttke,i have also cleaned it
Customer: replied 2 years ago.
the driving it in reverse with no problems and not forward is something ive never seen happen
Expert:  AZTechBrian replied 2 years ago.

Ok. Im at a loss at the moment. I am going to throw this question someone elses direction. I'm sure it's something that someone here has seen before and can tell you what's up. If I think of something I'll let you know.

Customer: replied 2 years ago.
ok
Expert:  GM Bob replied 2 years ago.

Hello my name is ***** ***** I can help.

I have seen the main wire harness rubbed through causing a Shorting out of some wires.

This normally happens at the driver side front just below the air filter box. The wire harness is rubbing at the trans housing or the A/C lines/dryer

Let me know if this helps

Customer: replied 2 years ago.
that was one of the first things I did was the wiggle test on the wiring harness,motor mounts are good also
Expert:  GM Bob replied 2 years ago.

It only does it when in drive. Can you hold the brake and give it gas to make it stall?

If so try having some one move the wires than see if you can stop it from stalling.

Customer: replied 2 years ago.
ive done that with my wife working the gas,it seems now it starts to run ruff when u first start it,smells rich
Expert:  GM Bob replied 2 years ago.

Do you have a scan tool?

If so does it read live data?

Customer: replied 1 year ago.
I have a scan tool,again if I foot brake it in gear to 1500 it will cut off,if I take off in gear when it gets to 1500 rpm it will cut of,but I can drive it all day in reverse it runs fine..this thing is killing me..
Customer: replied 1 year ago.
I have a snap on solus
Expert:  GM Bob replied 1 year ago.

Have you also checked the wire harness that is on the right of the engine? I have found some wires damaged there.

The under hood bussed electrical center wiring harness.

Customer: replied 1 year ago.
I have pulled,yank,and checked for rubson all the wires will engine is running,i can also get it to do it by patting the gas in park sometimes
Expert:  GM Bob replied 1 year ago.

Can you tell if the Engine control module see the trans going into drive?

Is it cutting out or is it like a rev limiter?

Customer: replied 1 year ago.
its cutting out
Expert:  GM Bob replied 1 year ago.

Do you know how to post a video ether here or YouTube?

I would like to see what it is doing.

All so can you scroll through the data list and video it when it is cutting out?

Customer: replied 1 year ago.
not computer savey so uploading a vid will be a problem..this is a auction car I bought,something I notice,this 3.8 supercharged engine has two map sensors,only one has vacuume going to it,is this right
Expert:  GM Bob replied 1 year ago.

Yes that is normal one is a MAP other is a BARO sensor

Customer: replied 1 year ago.
i found some what of the problem,i can unplug the egr and the problem goes away,so I replaced egr valve,problem still there with new one.only way it runs right is with the plug disconected
Customer: replied 1 year ago.
ive checked the egr wires to the computer for rubs or wires touching,all look good
Expert:  GM Bob replied 1 year ago.

With your scan tool are you getting any vehicle speed reading or is your speedometer jumping? When sitting still

The egr valve should only open when moving

Customer: replied 1 year ago.
all wheel speed seonsors are showing 2,also have a c0240 code
Expert:  GM Bob replied 1 year ago.

That is a normal reading for the ABS. Code C0240 set because the is a PCM code set.

The PCM detects a malfunction and then causes TCS shut down until the malfunction has been corrected.

I wanted to know if the trans output sensor is showing any speed.

What codes do you have set in the PCM?

Are they EGR codes because you disconnected it?

Customer: replied 1 year ago.
0403 0405 egr codes since ive been pluging and un pluging,there are no output speed showing while sitting still in park or in gear
Expert:  GM Bob replied 1 year ago.

Was this problem happening before you replaced all the parts you listed?

Can you scan tool read the VIN# ***** the PCM? Does the PCM/ECM look like it was replaced?

Customer: replied 1 year ago.
the problem has been there the whole time and I have been throwing parts at it,the pcm thats located in the air box is clean,looks to be a factory and when I read the vin on scanner it matches up with cars vin
Customer: replied 1 year ago.
should I try a pcm ?
Expert:  GM Bob replied 1 year ago.

Plug everything back in. Try unplugging MAF sensor

Customer: replied 1 year ago.
ive replaced the mass sensor already and have tried that with no luck
Expert:  GM Bob replied 1 year ago.

Have you test drove the car with the EGR unplugged?

With it plugged back in. What does your scan tool show what the ECM is requesting?

Customer: replied 1 year ago.
I did just go out there and uplug the mass since I haven't tried it with the new egr,car will not take gas and wont hardly run with it un pluged,no I have not drove car with egr unplugged,just foot braking it to see if it will go beyond 1500 rpms which it does,what do u mean by what ecm is requesting ?..thanks for the help !
Expert:  GM Bob replied 1 year ago.

When you look at live data there should be ECM comannd EGR % opening and actual % opening.

Customer: replied 1 year ago.
I will let u know Monday..thanks
Expert:  GM Bob replied 1 year ago.

Ok just keep me updated

Customer: replied 1 year ago.
ok,my scanner only shows egr position %,it stays at 0 weather I have it pluged up or not,sitting still or moving
Customer: replied 1 year ago.
I did find the opening and actual in my misfire screen,the both read the same when called on with plug hooked up,even when its stalls there even,un plug the egr and all is good..wth !
Expert:  GM Bob replied 1 year ago.

So with the EGR vale plugged in you can see the actual opening on the scan tool?

What is the reading?

Did you drive it with the EGR valve unplugged?

I just need to know have you ever taken the car on the road?

Customer: replied 1 year ago.
I drove car ,will not drive past 1500-1800 rpms.as soon as I take off and it gets to that rpm it cuts off,both readings on the scanner are the same till it gets to that 1500 1800 rpm,but whe I unplug it,it drives down road with no problems..check engine light comes on.i am also getting a 0300 miss fire code,#4 is showing a miss at idle but goes away when going down the road,it has the orig wires and plugs I believe..will go in reverse and drive with egr pluged up with no problems
Expert:  GM Bob replied 1 year ago.

Have you tried running it with the exhaust converter unhooked?

I think you my have a restricted converter.

Customer: replied 1 year ago.
no I haven't,i will try that in the morning..i also have a tool I can check back pressure by putting it in a 02 sensor before the converter
Expert:  GM Bob replied 1 year ago.

You could take the 02 sensor out and drive it see if it helps.

Customer: replied 1 year ago.
ok,i put my back pressure gauge on the 02 right before the converter,showed 0 back pressure..i also hook up egr wire to test drive with the 02 out also,,as soon as it gets to 1500-1800 it shuts off..this thing is killing me bob !
Expert:  GM Bob replied 1 year ago.

I know I'm trying my best to help.

Did you do a crankshaft position variation relearn?

Customer: replied 1 year ago.
I did..
Expert:  GM Bob replied 1 year ago.

The rpm you are looking at is on the scan tool?

Customer: replied 1 year ago.
no,im looking at rpm on car
Expert:  GM Bob replied 1 year ago.

See what the scan tool shows.

Customer: replied 1 year ago.
scanner shows same rpm as gauge on car when it shut down
Expert:  GM Bob replied 1 year ago.

The engine should not stall even if the EGR is fully open at the RPM you are running. If you let off and it is still at 100% than it will stall.

We are just over looking something.

Customer: replied 1 year ago.
why does it not stall with the egr un pluged,something weird is going on here,could those wires be shorted when its hooked up causing some kind of freak problem
Expert:  GM Bob replied 1 year ago.

I'm sorry for the delay. I can't think of anything to help with out driving it.

Sorry I will opt out.

Thank you