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1987 Pontiac Grand Am Power Loss

1987 ALL OTHER MAKES ALL OTHER MODELS
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BUSTERBEALL
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  • 2 POSTS
I have a 1987 2.5 Automatic with 170,000 mi.
The problem is that the car will intermittently lose power while cruising. The check engine light will come on and the speedometer will fall to zero for a brief second and then pick right back up. I have recently changed the fuel filter but it had no effect.
No DTC is being stored in the computer either.
Once in a while the check engine light will pulsate at what appears to be engine speed --really weird.
Also, sometimes it will high idle for no reason as well.
Any help will be greatly appreciated.

Just sent a Donation as well...
Dec 23, 2006 at 2:21 AM
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2CARPRO JACK
  • ✓Experienced Mechanic
  • 11,533 POSTS
Sounds like an intermittent electrical problem. Start with the basics, have the alt and battery tested.Check all grounds and power feeds.Might have n main PCM relay thats giving up on you. This one might require some diagnostic equipment to find. Good luck
Dec 23, 2006 at 11:44 PM
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Suggested Repair

Treat this as an intermittent electrical fault. Test the alternator and battery, inspect grounds and power feeds, and check the main PCM relay. Further diagnosis may require scan or electrical test equipment.

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Conversation Summary

The owner of a 1987 Pontiac Grand Am with a 2.5 automatic reports intermittent power loss while cruising, a brief speedometer drop to zero, and a check engine light with no stored codes. The light sometimes pulses with engine speed, and the engine occasionally idles high. A fuel filter replacement did not help. The expert suspects an intermittent electrical problem and recommends testing the alternator and battery, checking grounds and power feeds, and considering a failing main PCM relay, possibly with diagnostic equipment.

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