RPM's fluctuate

Tiny
JSALZ
  • MEMBER
  • 1994 FORD F-150
  • 5.0L
  • V8
  • 4WD
  • AUTOMATIC
  • 136,000 MILES
Start truck up rpm's go up to 2000 rpm's, then drop down to 1500 rpm's and then goes down to 900 rpm's. When put into reverse and drive I have it set to ten degrees BTDC, then it goes up to 18 to 25 with spout connector in, are the rpm's supposed to be in that range?
Thursday, March 2nd, 2017 AT 4:12 PM

4 Replies

Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Try cleaning throttle plate on both sides and shaft area and IAC hole with choke cleaner. Check for a vacuum leak and broken grommets on valve covers etc.
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Friday, March 3rd, 2017 AT 7:24 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Hey JSALZ,

I have seen where a worn distributor drive gear will cause the problem you are describing, can you remove the distributor and look for excessive wear please.

Please let us know what happens.

Best, Ken
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Monday, March 6th, 2017 AT 10:51 AM
Tiny
JSALZ
  • MEMBER
  • 13 POSTS
The distributors new got it up and running, thanks!
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Monday, March 6th, 2017 AT 6:17 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Good to hear, please use 2CarPros anytime we are here to help.

Best, Ken
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Tuesday, March 7th, 2017 AT 11:17 AM

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