Idle surges

Tiny
JCC0111
  • MEMBER
  • 1999 FORD F-150
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 91,000 MILES
My f150 pickup when I start it up about 60 second later the idle will go up and down like some one giving it gas and them let offf on it and them start missing a little but never die off it
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have the same problem?
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No
Friday, February 29th, 2008 AT 5:50 PM

45 Replies

Tiny
MASTERTECHTIM
  • MECHANIC
  • 4,749 POSTS
Is the check engine light on? Have you tried cleaning the throttle body?
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Friday, February 29th, 2008 AT 6:12 PM
Tiny
JCC0111
  • MEMBER
  • 2 POSTS
Yes the engine light is on but no I never have try that is that hard to do?
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Saturday, March 1st, 2008 AT 9:25 PM
Tiny
DONKPUNCH
  • MEMBER
  • 1 POST
  • FORD F-150
I have a 1997 ford f150 4.6 with 108,000mi. Great running truck until the heater core blew. I removed entire dash (lots of fun) and made the repair. I started the truck and let it warm up, heater blew hot and no leaks. I turned off the engine and while I was at it, replaced the air cleaner, fuel filter, and added some Lucas injector cleaner. Later, when I went for a drive, the truck ran normal except that when I came to a stop it would hesitate and die. It idles fine in all gears until it warms up, and then only in neutral and park. I am able to restart the truck immediately in park and neutral. No trouble codes, though I have replaced the IAC sensor to no avail. I guess the question is, what could I have done or not done to cause this problem? Thanks!
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Monday, June 8th, 2020 AT 5:10 PM (Merged)
Tiny
FORDTECH1
  • MEMBER
  • 23 POSTS
I would look for a vacuum leak or any other hoses that could of got unhooked. There cant be any leaks in the air intake system beyound the mass air flow sensor. The mass air flow sensor has to see all the air that enters the engine.
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Monday, June 8th, 2020 AT 5:10 PM (Merged)
Tiny
2CARPRO JACK
  • MECHANIC
  • 11,533 POSTS
Try following the PCV line to where it hooks to the engine. The elbows tend to go soft and create a vacuum leak
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Monday, June 8th, 2020 AT 5:10 PM (Merged)
Tiny
TXREBEL
  • MEMBER
  • 1 POST
  • 1997 FORD F-150
  • V8
  • 4WD
  • AUTOMATIC
  • 153,000 MILES
Hello I have a 97 f150 with a 5.4 liter engine usually I can diagnose and fix whats wrong but im stumped. One day it was running fine and then 5 minutes later it was crap. In order to keep the engine running I have to feed it gas it only idles at 500 rpm and then dies after a few secs the air in the cab will only blow throught the defrost and I have a problem stopping I know from these problems you would think vacum leak but I cant find it I have replace the pvc valve egr valve idle air control motor throttle body gasket and maf sensor along with a few vacum hoses that where dry rotted I have even cleared the computer but I still have no change in the way it runs plz help me figure this out sincerly brian in texas
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Monday, June 8th, 2020 AT 5:10 PM (Merged)
Tiny
BLACKOP555
  • MECHANIC
  • 10,371 POSTS
First change the plugs and wires, also check distributor cap rotor, or coil packs/coils.

Once you do that start it up and let it run a bit, then spray carb cleaner or starting fluid all over the vaccum lines and around the intake manifold base, if the idle goes up or down you have found your vaccum leak.
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Monday, June 8th, 2020 AT 5:10 PM (Merged)
Tiny
REXDOWNEY
  • MEMBER
  • 1 POST
  • 1995 FORD F-150
  • V8
  • 4WD
  • MANUAL
I have a 1995 5.0 f150 and I am having problems with the idle. I have already replaced the idle switch but that didnt seem to be the problem, do you possibly know what else the problem could be?
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Monday, June 8th, 2020 AT 5:10 PM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,758 POSTS
You may have a bad IAC ( idle air control) but try eliminating any vacuum leaks and cleaning the throttle body first. Remove the intake snorkel, have someone hold the throttle wide open for you and scrub the back side of the throttle plate and surrounding bore with an old tooth brush and some carb cleaner. Be sure to spray some into the small holes next to the throttle plate. That should help stabilize the idle. If it still has a problem, replace the IAC.
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Monday, June 8th, 2020 AT 5:10 PM (Merged)
Tiny
JHNBAPST
  • MEMBER
  • 4 POSTS
  • 1995 FORD F-150
  • 150,000 MILES
I have a 95 f150 4x4 5.0 when I start it when its cold outside itll start fine and accelerate high for about 10 seconds but then die down immediately almost stalling ive changed the iac valve but ill the same issue where should I go next? I was thinking the coolant temp sensor
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Monday, June 8th, 2020 AT 5:10 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,005 POSTS
Check for vacuum leaks.
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Monday, June 8th, 2020 AT 5:10 PM (Merged)
Tiny
JHNBAPST
  • MEMBER
  • 4 POSTS
CAN THE COOLANT TEMP SENSOR TELL THE COMPUTER THE ENGINE IS WARMED UP BECAUSE THE CHECK ENGINE LIGHT WILL TURN ON RIGHT WHEN THE IDLE DROPS
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Monday, June 8th, 2020 AT 5:10 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,005 POSTS
Have you checked for trouble codes?
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Monday, June 8th, 2020 AT 5:10 PM (Merged)
Tiny
JHNBAPST
  • MEMBER
  • 4 POSTS
No I havent where can I get that done on a 95
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Monday, June 8th, 2020 AT 5:10 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,005 POSTS
95 should be an OBD2 system. Most parts stores will do it for free.
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Monday, June 8th, 2020 AT 5:10 PM (Merged)
Tiny
JHNBAPST
  • MEMBER
  • 4 POSTS
Thanks a lot ill see what I can do and let you know I appreciate your feedback
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Monday, June 8th, 2020 AT 5:10 PM (Merged)
Tiny
JAY ADKINS
  • MEMBER
  • 11 POSTS
  • 1996 FORD F-150
  • 150 MILES
I remove the distributor to replace the stator. When I put it back together the timing is way off. I've done all the basics. Found tdc on compression stroke at number one. Put in dist. And had rotor facing number one. Removed the spout. I can't figure out why the timing is off. It starts but jerks go's up and down in rpms, I've turned the dist. 90 degrees in both directions and it only gets worse. I tried putting back in the spout and it just shut off. I don't know why the timing is so far off. Before I removed the dist. The timing was spot on. Whay am I missing. 96 150 4x4
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Monday, June 8th, 2020 AT 5:10 PM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,758 POSTS
This is an OBD1 system and you are going to need a professional scan tool for this one.
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Monday, June 8th, 2020 AT 5:10 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,606 POSTS
You need a pro type scanner to get it where it is supposed to be they can find the fewdegrees where it should be. Try cleaning throttle plate on both sides with chokecleaner as well
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Monday, June 8th, 2020 AT 5:10 PM (Merged)
Tiny
JAY ADKINS
  • MEMBER
  • 11 POSTS
I appreciate the reply, but if it was even close shouldn't I be able to get it close enough without a timing light so that it would at least be able to run somewhat decent? Also, when the timing does get set, do I put the spout bar back in? I'm no expert like you, but I am somewhat of a decent home mechanic, and I've been working on 302"s and 351"s for many years. Although it's been a few years since the last time I had a sever timing issue to deal with, the last time was a 302 on a 90"s model crown vic, and I was able to dial it in almost perfect by sight and ear. I just don't understand what could be making it be this far off. There has to be something simple i'm missing, but I just can't figure it out, and the timing was too good prior too this for it to seem logical that it's a timing chain issue. The reason I replaced the stator is because it woul

Thanks
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Monday, June 8th, 2020 AT 5:10 PM (Merged)

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