1986 Other Ford Models power problems

Tiny
A. D. PHILLIPS
  • MEMBER
  • 1986 FORD
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 250,000 MILES
I have a 1986 Ford Bronco2 with the 2.9L EFI V-6. It really has a problem pulling a hill. It lunges and jerks and I usually have to pull it down into a lower gear to get up the hill (which makes it lunge and jerk all the more). It never backfires so I don't think it's the cam. Running down flat road it runs great.
I've replaced the Air Bypass Valve, the TPS, the Fuel and Air filters, had a complete tune-up, had the timing checked, made sure there were no vacuum leaks, It's not jumping fire and the throttle body is spotless. (Never a check engine light)
Does anyone have any suggestions?
Thursday, May 8th, 2008 AT 10:37 AM

3 Replies

Tiny
THIS IS MIKE
  • MECHANIC
  • 686 POSTS
Check your catalytic converter, it may be plugged causing your power problems while going up hills. The exhaust should be hotter out the back of the converter. If the converter is the same temperature front to back the converter is bad and needs to be replaced. Sometimes when a converter fails, the catalyst material can break up, restricting the exhaust flow robbing power. Under low load driving this condition is harder to detect.

https://www.2carpros.com/how_does_it_work/catalytic_converter.htm
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Thursday, May 8th, 2008 AT 4:00 PM
Tiny
A. D. PHILLIPS
  • MEMBER
  • 4 POSTS
Mike, Thanks for the reply but this truck doesn't have a converter anymore. I forgot to mention that in my post. Anything else you can think of?
Thanks for the effort!
Tony Phillips
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Thursday, May 8th, 2008 AT 8:15 PM
Tiny
THIS IS MIKE
  • MECHANIC
  • 686 POSTS
Next I would check the compression in all cyclinders. Check your fuel pressure. When was the last time you changed the timing chain? Check for play in the timing chain.
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Friday, May 9th, 2008 AT 2:16 PM

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