1998 Pontiac Grand Prix Engine Problem

Tiny
LSHON
  • MEMBER
  • 1998 PONTIAC GRAND PRIX
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 168,000 MILES
Car stutters when going after a complete stop or over 40 miles per hour. I do have a supercharger in it.
Monday, July 20th, 2009 AT 6:54 PM

7 Replies

Tiny
MMPRINCE4000
  • MECHANIC
  • 8,549 POSTS
Start by checking fuel pressure with mechanical gauge. Fuel pressure should be at least 45psi and increase as throttle is "blipped".

If OK, then remove and clean the EGR valve and Idle air control valve.

If problem persists, then it MAY be transmission related (torque convertor clutch for example).

But a good starting point is fuel pressure.
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Tuesday, July 21st, 2009 AT 8:37 AM
Tiny
LSHON
  • MEMBER
  • 4 POSTS
Thank you so much for your reply, I will definitely look into it. I will keep in touch.
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Tuesday, July 21st, 2009 AT 10:29 AM
Tiny
MMPRINCE4000
  • MECHANIC
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Another possibility is a clogged or partially clogged CAT. If, after running the car for 20-30 miles, park it and look at convertor, if it glows red, then it is overheating and most likely will need to be replaced.

Just another possibility.
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Wednesday, July 22nd, 2009 AT 8:10 AM
Tiny
LSHON
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  • 4 POSTS
Thank you so much! I was told that I need a transmission & plugs need to replaced. My question is, is this worth fixing? Old engine, new transmission, good question.
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Wednesday, July 22nd, 2009 AT 10:42 AM
Tiny
MMPRINCE4000
  • MECHANIC
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Wheather it is worth it or not is up to you. You can look at local junk yards for a used trans.
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Thursday, July 23rd, 2009 AT 7:44 AM
Tiny
LSHON
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  • 4 POSTS
Thank you! I will consider that.
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Thursday, July 23rd, 2009 AT 12:29 PM
Tiny
MMPRINCE4000
  • MECHANIC
  • 8,549 POSTS
Many people opt for a used trans vs a new/rebuilt. The only problem is that labor is not covered to remove/install them if they are bad ones.
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Friday, July 24th, 2009 AT 7:29 AM

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