Question about 1993 Pontiac Grand Prix

1 Answer

1993 pontiac grand prix 3.1 liter

The engine runs fairly smooth at idle but when you put it into drive it runs rough. We have replaced the fuel filter, fuel pump , fuel regulator, fuel injectors, plugs and wires, and the throttle position sensor as well as the map sensor. The only codes thrown were the tps and the map sensors. The compression checks out great and the engine does not smoke. At an idle if you full throttle it the engine cuts out and surges. We cannot find any vacuum leaks either. Funny, it passed emissions as well earlier in May of this year as well. Now what?????

Posted by on

  • 2 more comments 
  • dwiley41 Sep 22, 2008

    Checked EGR, it was fine. Had a 5 volt reference at both the tps and the map. However I did find that the coil was bad on the #1 and #4 cyllinders. Runs much better now but in park when you full throttle it it still cuts out. In drive though it is not noticable. It runs well enough that I think we will leave alone for now. Thanks for the help. The note to check the plug wires helped me to find the bad coil. Oh, something strange though. When I energized the wiring to check the egr, all of the wires operated the solenoids correctly. However when I energized the fourth wire a strange thing happened. The a/c fan inside the car came on. Any idea why that would happen????

  • dwiley41 Sep 27, 2008

    Now we have a different problem with the car. Transmission (125 c) The owner was able to drive her car home running great for the first time in 3 years. After driving the car 1 day running well , she parked her car in the parking lot of a Walgreens, went in and came back out and now has no reverse or park. The car will still start, but it starts in drive. There is no park at all and no reverse. It also creeps forward in neutral. We pulled the pan and found a few small pieces of what looks like clutch material but not much. Drove it out, briefly, and the car has all the forward gears. I think I am going to get a Molatov cocktail......Any ideas? Oh, by the way, The reason I had not checked the coil in the first place is that the owner's boyfriend of the car had told me that he had replaced the wires and checked spark and compression already. He is a young mechanic that just graduated so I assumed he knew what he was doing......

  • dwiley41 Oct 04, 2008

    Just in case anyone out there had this problem, it turned out that the transmission needed rebuilt due to worn clutch plates. Evidently after we got the engine running correctly the extra power finished off the already worn out clutch packs and the reverse band. We rebuilt it for about $150 when transmission shops were going to charge us about $1800 - $3800.

  • Anonymous Mar 21, 2014

    it starts up idles low 500rpm give it throttle n only gets 2500-3000 rpms I think I hear a slight nock.i have done the following new plugs,map sensor,camshaft position sensor,camshaft acturator solenoid,cleaned furl line and enjecter rail,fuel filter.and all this made no difference.The check engine light is on code is po300 which is random or multy misfire.can any1 help? please

×

1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

    Vice President:

    An expert whose answer got voted for 100 times.

  • Master
  • 335 Answers

The 3.1 had some EGR problems, EGR valve stuck open, blown diaphrams, Plugged passages Im not saying that is all your problems and I believe yours has whats called a linear EGR about $350.00 from the dealer (and that is the only place you ever consider buying such a critical part for the emissions system regardless of the cost)
That car is so antiquated as far as computers go that relying on the codes is nearly pointless! Map code can set because of low engine vacuum which you will have with a poor running engine, Check for 5 volt reference voltage at the TPS and MAP with the key on and engine off if no 5 volt reference I suspect a Computer. Computer Ground is on the Thermostat housing and needs to be clean and secure.
There is a legit test in the GM factory manual called the TAP TEST take the ECM (computer) and slap it with an open hand, if the symptoms change the ECM is bad it's very common in the early-mid 90s for the computers to go bad in one way or another the circuit boards come loose and suffer also from cold solder joints.
Make sure the wires are on the correct plugs and hopefuly you used factory plugs and wires and No split fire or bosch plugs only AC delco
Make sure you have good spark on all 6 cylinders.
Contact me at fixincars@yahoo.com with the results and any feedback or questions

Posted on Sep 19, 2008

  • Randy Harkins
    Randy Harkins Sep 22, 2008

    you should never do a full throttle test the cutting out is the govenor to save the engine from overspeed, I am glad you found it and dis not assume you had a bad coil because you mentioned having changed wires and plugs and I thought you would have checked that but anyway thanks for the feedback and good luck and please if you like visit my website I created it while I was in business in my diagnostic shop for 14 years.

    http://www.aceautomotive1.com

  • Randy Harkins
    Randy Harkins Sep 27, 2008

    Ok I'll look into this and get bck to you tomorrow ,sorry busy all day today sorry.

×

Add Your Answer

Uploading: 0%

my-video-file.mp4

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

×

Loading...
Loading...

Related Questions:

1 Answer

1993 pontiac grand prix se 3.4 manual trans surges after warm up


Have you run a fault code test on the engine control module?

Oct 06, 2016 | 1993 Pontiac Grand Prix

1 Answer

Engine surges at about 4000 rpms. vechile wont go past 40mph on steep hill


Start by checking your fuel pressure. You should ave 5-10 lbs of pressure. If you don't have that amount of pressure you should check your fuel filter. If you check your filter and it is clear and you have the right amount of fuel pressure then you may have an injector problem that is best solved by replacing all of the injectors. If non of this helps please give more information on how the engine runs at idle (smooth, rough, spit, spudder) and such as that as you may have an ignition problem.

Mar 04, 2015 | 1993 Pontiac Grand Prix

1 Answer

2000 gran prix 3.1 runs fine while driving, but when stopped at a light starts to idle rough


Take the EGR Valve off and clean all the carbon out of it using something to scrape with and use a non-chlorinated brake cleaner.Whenever an EGR Valve gets stuck in the open position it allows exhast gasses into the intake manifold causing the engine to idle really rough,but after you get up to say 45-55 its smooths out thats when the valve should be open.

Apr 19, 2011 | 1999 Pontiac Grand Prix

3 Answers

I have a 97 grand prix gtp that will start but wont hold an idl


bad fuel pump.- just replace it and your good to go!

Feb 21, 2010 | 1997 Pontiac Grand Prix

2 Answers

1993 grand prix dying


provided you don't have a vacuum leak, (check all hoses for tightness and cracks with engine running) it's probably your idle air control valve or sensor.

May 21, 2009 | 1993 Pontiac Grand Prix

1 Answer

Rough idle


had the same issue with mine, a full tuneup and a really good cleaning for the throttlebody cleared mine up.

Apr 18, 2009 | 1993 Pontiac Grand Prix

1 Answer

BAD RUNNER


Check the fuel pressure regulator. Pull off the vac line to it and see if any gas is leaking out of the vacuum fitting. If you see any fuel replace the regulator.

Mar 30, 2009 | 1993 Pontiac Grand Prix

1 Answer

V6 engine idles rough after restarting, then smooths out


My first guess would be a dirty carb/fuel injector set. Run some fuel cleaner through the tank and see if it gets better. You might have to do it through a couple of tanksful. How long since you've had a tune-up? It might just be that time.

Nov 15, 2008 | 1993 Toyota Pickup

1 Answer

Idle problem


throttle position sensor is what I replaced on mine. Could also be a short in a wire that controls throttle. That was 6 years ago and it was $100. Took it to a shop, that's all I got.

Jun 24, 2008 | 1993 Pontiac Grand Prix

Not finding what you are looking for?
1993 Pontiac Grand Prix Logo

1,056 people viewed this question

Ask a Question

Usually answered in minutes!

Top Pontiac Experts

yadayada
yadayada

Level 3 Expert

61168 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

21949 Answers

Jeff Turcotte
Jeff Turcotte

Level 3 Expert

6812 Answers

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

Answer questions

Manuals & User Guides

Loading...