1994 Ford F-150 idling

Tiny
PORTHOS1
  • MEMBER
  • 1994 FORD F-150
  • V8
  • 2WD
  • AUTOMATIC
  • 125,000 MILES
I think the answer is simple. I had some issues with my oil pressure and you guys gave me good advice which worked fine. Now my idle is acting up. It will start perfect and run. After a few minutes or so the idle will drop down from its cold start and then down more. When it gets to it leveling off rpm it goes down to barely running then at the last second it saves itself. Then it will do it again. And finally it just dies. I can start right back up again. I removed and cleaned the idle control vavle and it was fairly dirty but still same result. Is that even possible to clean and second my thoughts were maybe throtlle position sensor. Side note- when I drive it and it doesnt die it has a little hesitation and sometimes it just ramps up like nothing is wrong.
Sunday, August 29th, 2010 AT 10:47 PM

7 Replies

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Hi porthos1, Welcome to 2carpros and TY for the donation

Clean the MAF sensor with an electronic cleaner CRC and test the throttle position sensor-to include cleaning out the EGR valve
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Sunday, August 29th, 2010 AT 11:54 PM
Tiny
PORTHOS1
  • MEMBER
  • 49 POSTS
I cleaned the maf sensor and replaced the egr valve because it was old and rusty looking. Still doing the same exact thing. Runs for 1 min or 2 and then slowly dies and then sometimes catches itself and ramps up to level and then dies. I think the IAC.
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Tuesday, August 31st, 2010 AT 4:15 PM
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Clean out the idle air control valve thoroughly and see what happens
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Wednesday, September 1st, 2010 AT 3:12 PM
Tiny
PORTHOS1
  • MEMBER
  • 49 POSTS
I replaced the IAC. Still doing it. I found a broken vacuum hose going to the fuel regulator. I changed it and same results. But wonder if the vacuum hasnt been working properly could the fuel regulator gone bad or messing up? Cause it made no difference with the vac hose on it or off. Running wise I mean.
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Wednesday, September 1st, 2010 AT 3:37 PM
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Testing the fuel pressure regulator engine idling:

Check if you have vacuum on the FPR hose if so-Get a fuel pressure tester and hook it on the test port and record the pressure reading, now disconnect the vacuum hose plug it, the fuel pressure should increase about 8-10psi

Also test the throttle position sensor
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Wednesday, September 1st, 2010 AT 3:53 PM
Tiny
PORTHOS1
  • MEMBER
  • 49 POSTS
LIke you said the regulator did go up about 8 psi when I removed the hose. I already ohmed out the tps and checked what was going back to the computer. All good.

Running out of ideas. I appreciate your help.
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Friday, September 3rd, 2010 AT 10:34 AM
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Check and test the coil, distributor pick-up coil and ignition control module
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Friday, September 3rd, 2010 AT 12:31 PM

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