1990 Ford F-250 F-250 Will not idle.

Tiny
BRANDEN967
  • MEMBER
  • 1990 FORD F-250
  • V8
  • 4WD
  • AUTOMATIC
  • 130,000 MILES
Hello,
Thanks for taking the time to view this. I have a 1990 Ford F250, 5.8 gas engine. It will not ide. It starts up fine but I have to feather the gas to keep it running. It bounces from roughly 200 RPM to 900 RPM, back and forth. I have replaced the IAC valve with a new one and got no change. I also removed the vacuum line to the EGR valve still nothing changed. Ive unpluged the EGR valve and didnt get anything to change. I removed the complete EGR valve and everything looked ok. I was able to press the pin and the valve moved ok. It did not seem like it was stuck. I tried running it without the EGR valve pluged in and it again did the exact same thing.

Any sugestions would be greatly appricated.

Thanks,

Branden
Sunday, May 2nd, 2010 AT 6:10 PM

5 Replies

Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
You may have a vacuum leak, get a can of spray Throttle body cleaner, spray the vac lines and maniflod area, when the idle changes, youve found the leak! You want the engine running and spray on the outside but do direct the stream onto the hoses, if it is a vacuum leak, the engine idle will change speed, then you have detected a leak, repair the vacuum leak and see how it runs! If the check engine light is on, let me know, I will tell you how to read the flash codes. Anyone changed the trany screen lately? If the screen popped off the tube, it will also stall when placed in gear. Pinch off the power brake booster hose and see if it helps.
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Tuesday, May 4th, 2010 AT 2:37 PM
Tiny
BRANDEN967
  • MEMBER
  • 3 POSTS
Thanks for the help. I'll try the vac line hunt tonight. I dont think its the trany screen because it does the idle issue regardless of in or out of gear. But the check engine light is on. How do you read it for that year.

Thanks,
Branden
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Tuesday, May 4th, 2010 AT 4:22 PM
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS


https://www.2carpros.com/forum/automotive_pictures/62217_Codes1_1.jpg



https://www.2carpros.com/forum/automotive_pictures/62217_codes2_1.jpg



https://www.2carpros.com/forum/automotive_pictures/62217_codes3_1.jpg



https://www.2carpros.com/forum/automotive_pictures/62217_codes4_1.jpg



https://www.2carpros.com/forum/automotive_pictures/62217_connector2_1.jpg

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+3
Wednesday, May 5th, 2010 AT 12:51 PM
Tiny
BRANDEN967
  • MEMBER
  • 3 POSTS
Hello,
Well Im stumped yet again. I went through all of the tests and I still can't figure it out. I sprayed all of the vacuum lines, clamped the brake booster hose and a couple of other little things but still can't figure it out.
I read the check engine codes and on the engine running test I got code # 998 which I believe was a hard fault. Whatever that means. During the engine off test it kept giving me code #223 which I believe just comes up because the engine was off.

Any suggestions would be greatly appreciated.

Thanks,

Branden
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Wednesday, May 12th, 2010 AT 7:47 PM
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
223. Loss of Dual Plug Ignition Control
998. Fuel management mode problem
I'll look into these later today, I'm off to my real job.
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Thursday, May 13th, 2010 AT 2:56 AM

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