1994 Pontiac Grand Prix car stutters going up hills

Tiny
PATTI0117
  • MEMBER
  • 1994 PONTIAC GRAND PRIX
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 187,000 MILES
Ran fine, very good car with no burning of oil or any problems whatsoever. Then, blew a head gasket, which has been replaced. Put in new spark plugs, changed fuel filter. Ever since the car runs fine at a steady speed, even at 80 miles per hour. If, you are at bottom of a hill and not going fast then if you try to increase the speed it will stutter and shudder and totally bog down. Any suggestions
Friday, July 17th, 2009 AT 12:43 PM

2 Replies

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Check the listed components below and get back with some results

Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)

Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include:

Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires
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Sunday, July 19th, 2009 AT 12:31 AM
Tiny
MMPRINCE4000
  • MECHANIC
  • 8,548 POSTS
I would start by checking the compression on the repaired head.

It may also be a valve problem, or clogged CAT, due to head gasket blowing.
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Sunday, July 19th, 2009 AT 8:09 AM

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