Question about Pontiac Grand Prix

1 Answer

Only runs full throttle

Start the car and its full throttle. ive changed the tps and other sensors.. sprayed the motor for vac leak. nothing.. now im stuck and dont know where to go from here.. the car just wants to max out and run as fast as it will go.

Posted by on

1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 20 achievements.


    An expert that got 10 achievements.


    An expert that got 5 achievements.

  • Pontiac Master
  • 5,252 Answers

Disconnect the MAF sensor and see if it changes rpm's. Pull off the big boot at the intake. Is the throttle valve wide open? If it is, the throttle body assembly needs cleaning-maybe it is stuck?
Have you scanned for trouble codes?

Posted on Jul 23, 2013

Testimonial: "the codes it threw were tps and 2 evac codes. im pretty sure its not stuck. "

6 Suggested Answers

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017

  • 321 Answers

SOURCE: buick lesabre nightmare

Need to get a scan tool and look at the data stream while it is running for alot more info.Also any trouble codes.Sounds like initially,the engine isn't getting any fuel.I would have a pressure gauge connected to the fuel rail on the engine,so i could monitor the fuel pressure while all this is going on.Items to look at on the data stream would be timing,what timing is the PCM commanding for the engine.Also,have you checked for continuos power feed to the coils during this no start condition,and fire at the plugs while cranking.You could possibly still have spark,but maybe it is extremely weak?I have seen bad ignition switches cause weird problems before too.Many things power up through the ignition switch,just a thought.Have also seen bad PCM's cause strange problems..38 volts is a little on the low side for GM.Usually see those at,at least .50 and up,and rise steadily while pressing the throttle,up to just under 5.0 volts.Potentiometer with 5 volt supply.Vacuum leak can be checked with engine running at a steady idle speed,spray brake cleaner all around the intake manifold and listen for engine speed change.

Posted on Jul 31, 2008

  • 255 Answers

SOURCE: buick lesabre no start

Hi you have replaced allmost everything ,(try fuel pump relay)

Posted on Aug 18, 2008

  • 2 Answers

SOURCE: my corolla 2000 1.8 dont respond well when i push the accelerator

its a dirty injector

Posted on Apr 15, 2009

  • 74 Answers

SOURCE: full throttle all the time

We actually have a TSB for the drive by wire systems that calls for both a TPS sensor/actuator replacement but it's required that you also do a PCM reflash at the same time. If you put in the new updated part without doing your reflash then you've found your problem.

Take it to the dealer and get the reflash done.

Posted on Nov 23, 2009

  • 4669 Answers

SOURCE: 84 Fiero. trouble starting and runs rough and the surges/stalls

It sounds like a fuel pump. Check the fuel pressure. What size engine?

Posted on Aug 01, 2010

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

Crown vic police interceptor 2003 when i start the motor, it runs about 2000rpm by itself. I understand some of electronics. So i changed the tps sensor but didnt fix the problem. Neither the fuel pump,...

Always start with the simple stuff.. look for vacuum leaks. look at accel cable attached to the throttle body.. is it stuck holding the throttle plate open? The big Vac hose from the intake manifold to the brake booster? . remove the big air hose from the airfilter to the throttle body check the throttle plate.. and clean the mass air.. special spray cleaner at auto parts store. Did this just happen or did you change something.. DID YOU INSTALL THE TPS WITH THE HOSE ON AND COULD NOT SEE THE THROTTLE PLATE POSITION?.

May 25, 2014 | Cars & Trucks

1 Answer

Solutions for 1998 grand marquis that will not idle

Have someone check the fuel pressure. Check EGR pod, you may have a Vacuum leak. Disconnect connector at a part called a TPS which is mounted on a Butterfly flap shaft opposite the throttle cable. Use an Ohmmeter on the TPS and check for smooth changes in Ohms as throttle is pressed.
If you get to the warmed up engine running part, use a water spray bottle and spray the seams of the intake and any Vacuum lines or fixtures you see. If the engine stalls or sputters then you have found the leak.

Aug 12, 2013 | 1998 Mercury Grand Marquis

1 Answer

Smell fuel leftside of engine

spray carb cleaner on the motor as it is running. Fuel leak will be more noticeable and engine will try to die when spraying. May be a bad throttlebody gasket at the base and it's not letting you see it.

Feb 01, 2013 | 1997 Chevrolet S-10 Pickup

2 Answers

Throttle stuck wide open

what make model year????? That would help everytime

Jan 08, 2013 | Chevrolet S 10 Cars & Trucks

1 Answer

93 talon hard to start runs rough untill it warms up. (backfires dies exetera)

I would start with checking the fuel pressure and boosting the fuel with spraying carb cleaner into the air intake hose.
It sounds like you are not getting enough gas into the cylinders.
Could be a vac leak too.

Sep 30, 2012 | Eagle Cars & Trucks

1 Answer

I have a 1997 chrysler intrepid sport with a 3.5l engine im haveing issues with it idling high i have cleaned and rreplaced the iacv it still is running high all the vaccum lines are all good no cracks...

it could be the tps, that is a prime candidate if the IAC is good-and you can check the intake for leaks (common on 3.5's) by taking a spray can of throttle body cleaner and spraying around the base of the intake runners, and the throttle body - listen for changes in idle while doing this.

Aug 08, 2011 | Chrysler Concorde Cars & Trucks

1 Answer

P2104 + p2112 car starts but runs rough an wont let me rev at all ends up dying out after a minute 2006 ford fusion

P2104--Throttle Actuator Control System-forced idle

P2112--Throttle Actuator Control System-stuck closed

That could be anything from-----simply spraying the throttle
plate with CRC Throttle Body Cleaner,to Coil misfires ,coming
back on your TPS Sensor and setting your codes,to a bad
APP Sensor (accelerator pedal position sensor) to worse
case,a bad TACM (throttle actuator control motor)

The TACM you never want,because it requires a complete
new throttle body from Ford --for the tune of over $600 just for the
part. That forces you to install yourself ,which is easy.

Spray the throttle plate and let me know if you have other
codes for misfires.

I hope you do not, still have 4 or 5 year old spark plugs
still in that motor. Get them out of there

Clean the MAF Sensor---CRC MAF Sensor Cleaner

Start doing this work yourself. You can not afford a thousand
dollars per visit at a dealer. I as others will help you out.

Mar 23, 2011 | Ford Fusion Cars & Trucks

2 Answers

Having the same problem on a 2005 4.3l....... replaced plugs, dist. cap, coils, and cam sensor. o2 sensor is good. idles great till you push the gas, then it misfires. timing was checked it was fine. ...

Something is probably leaning out the mixture when you open the throttle. It seems that any ignition issues have been ruled out.

So, check the following: fuel filter clogged, low fuel pump pressure, the fuel pressure regulator could be stuck at the idle setting, the EGR valve could be stuck open, faulty throttle position sensor (TPS) or circuit, faulty manifold absolute pressure (MAP) sensor, faulty or dirty manifold air flow (MAF) sensor, faulty intake air temperature (IAT) sensor, and an air leak into the intake duct or manifold between the MAF and the throttle body. I think if the intake manifold gasket had a leak, it would be misfiring at idle.

Ask the shop if any of the above checks have already been accomplished. I'll bet most of them have, but one may have been overlooked.

Feb 25, 2011 | 1998 Chevrolet C1500

2 Answers

Hi i have a 87 chevy k5 blazer with a 305 in it and im not getting any spray out of the injectors ive replaced the fuel pump the coil,fuel system relay and still nothing im out of ideas any help would be...

It could be the ignition module. The module sends a tach signal to the computer to fire the injectors. If the module fails and doesn't send the signal, the injectors won't fire.

Dec 14, 2010 | 1987 Chevrolet Blazer

1 Answer

My car runs good but has no power ,sounds like a vac problem!

the one thing i use is carburetor cleaner ,spray it at the vacuum lines and the throttle body plate as you do it you will see a change in idle if you spray the bad leak area.but if the leak is that loud it could be coming from the brake booster line or brake booster itself.hope this helps you.

Jan 31, 2010 | 2000 Hyundai Accent

Not finding what you are looking for?
Cars & Trucks Logo

Related Topics:

53 people viewed this question

Ask a Question

Usually answered in minutes!

Top Pontiac Experts


Level 3 Expert

74945 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22095 Answers

Jeff Turcotte
Jeff Turcotte

Level 3 Expert

7697 Answers

Are you a Pontiac Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides