Black smoke loss of power rpms jump all over

Asked by May 07, 2017 at 12:13 AM about the 2001 Pontiac Grand Prix GTP Coupe

Question type: Maintenance & Repair

I have a 2001 Pontiac grand Prix gtp
supercharged 3.8 liter v6 I have replaced the
IAC sensor tps sensor o2 sensors spark
plugs wires fuel filter and pump runs out of
gas at top of orange mark new mass air flow
sensor ecm new it still has the same
problem does anyone have the correct
answer of what exactly it is tired of wasting
money...Thanks

4 Answers

210

Check the cat and muffler

20,945

Check/test compression on all cylinders first and foremost to know if its worth any-more time/money. Running rich, fuel injectors may be dirty and to atomizing fuel any more.

1 of 1 people found this helpful.
261,775

I always diagnose before throwing parts at a vehicle. Is the Check engine light on? Scan for codes? Black smoke means running rich like engine creator mentioned. Is the car running on the cold side?

2 of 2 people found this helpful.
71,725

Definitely running rich. Fuel pressure regulator and/or fuel injectors leaking. These injectors are known for getting gumed up and becoming troublesome because of not spraying properly. Test the MAP sensor as well. A bad MAP sensor can make it go rich. What trouble codes do you have? With it running rich enough to produce black smoke, the service engine soon light has to be on! HTH. -Jim

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