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?
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Thursday, March 2nd, 2017 AT 4:12 PM

4 Replies

Tiny
HMAC300
  • MECHANIC
  • 48,606 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
  • 42,544 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
  • 42,544 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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