4.0 Stalling at Idle
Thread Starter
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Freshman User
Joined: Jul 2002
Posts: 47
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From: Alberta, Canada
4.0 Stalling at Idle
Hi All,
Got a persistant problem involving my 96' Ranger stalling at red lights, stop signs, etc. Seems to happen after the vehicle is warm. Never when cold.
I read many posts about stalling 4.0's and decided changed the IAC valve but still no difference.
This seems like a common problem...what's the next most likely recommendation for resolving the problem?
Got a persistant problem involving my 96' Ranger stalling at red lights, stop signs, etc. Seems to happen after the vehicle is warm. Never when cold.
I read many posts about stalling 4.0's and decided changed the IAC valve but still no difference.
This seems like a common problem...what's the next most likely recommendation for resolving the problem?
Post Fiend
Joined: Jul 2005
Posts: 8,462
Likes: 4
From: Durant, OK (SOSU)
Does it cough and sputter then die, or does it just die suddenly? Is the idle rough, or do you have any time to check it before it dies?
Since you went ahead and replaced the IAC (way to go), I'd first look for a possible fuel delivery problem by checking the rail pressure at idle. Check and clean the MAF sensor as well.
Since you went ahead and replaced the IAC (way to go), I'd first look for a possible fuel delivery problem by checking the rail pressure at idle. Check and clean the MAF sensor as well.
Thread Starter
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Freshman User
Joined: Jul 2002
Posts: 47
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From: Alberta, Canada
It doesn't really cough and sputter but goes into a low rpm (500rpms) that creates a rough idle. Eventually (within 20 seconds) it just dies.
Generally, within the 20 seconds, I always have time to step on the throttle to manually regulate the idle. When I regulate the idle back up to 1000rpms, it never stalls. I can then shift (with difficulty...auto tranny) into gear and start driving. By the next light, the problem is often gone. This may happen once per week...more when the weather is warmer.
I've cleaned the MAF before (a while ago), with no benefit. Since I just changed the IAC, I'll re-clean the MAF and see if it helps. Since the problem is extremely intermittant, I am inclined to think that fuel rail pressure is not the problem.
Generally, within the 20 seconds, I always have time to step on the throttle to manually regulate the idle. When I regulate the idle back up to 1000rpms, it never stalls. I can then shift (with difficulty...auto tranny) into gear and start driving. By the next light, the problem is often gone. This may happen once per week...more when the weather is warmer.
I've cleaned the MAF before (a while ago), with no benefit. Since I just changed the IAC, I'll re-clean the MAF and see if it helps. Since the problem is extremely intermittant, I am inclined to think that fuel rail pressure is not the problem.
Post Fiend
Joined: Jul 2005
Posts: 8,462
Likes: 4
From: Durant, OK (SOSU)
Shot in the dark here, hopefully one of the really good guys will show up. I had a problem with a low idle, really rough. Turned out to be the fuel relay, but I doubt that would be your problem. I'm almost inclined to believe either there's a problem with getting air in when the throttle is closed or you have a vacuum leak of some sort.
Post Fiend
Joined: Jan 2003
Posts: 9,748
Likes: 16
From: Connecticut
Check for a plugged PCV valve and hose. Clean the MAF sensor. If possible, do a fuel pressure check while the engine is warm. When's the last time the fuel filter was changed? Taking it a little further, when's the last time the truck had a tuneup?
Moderator
Joined: Jan 2004
Posts: 13,851
Likes: 111
From: SW Va
You might try having the computer scanned at your favorite autoparts store for any stored trouble codes, most will do it at no charge, if you're having problems.
Post all the code numbers found, with luck it may point to the problem, or at least to the toubled system, then we can probably make a better guess as to your root cause.
From your description of it only occuring when the engine is warmed up, it sounds like it's air/fuel based, rather than spark based, so the things listed that mess with the air/fuel ratio, or fuel delivery at idle are suspect & the list can get long without a good clue.
BUT, a clue you gave about it being a auto tranny & having problems shfting into gear, kinda makes me want to put it on the suspect list too.
If the lockup torque converter solenoid is acting up & not fully releasing, it could load the engne when stopping, kinda like stopping with the tranny in gear, on a straight drive!!!!
Have you tried shifting to "N" when it tries to stall???? If you do & it straightens up, suspect the tranny lock up solenoid.
So try having the computer scanned for codes & let us know all the code numbers they find.
Post all the code numbers found, with luck it may point to the problem, or at least to the toubled system, then we can probably make a better guess as to your root cause.
From your description of it only occuring when the engine is warmed up, it sounds like it's air/fuel based, rather than spark based, so the things listed that mess with the air/fuel ratio, or fuel delivery at idle are suspect & the list can get long without a good clue.
BUT, a clue you gave about it being a auto tranny & having problems shfting into gear, kinda makes me want to put it on the suspect list too.
If the lockup torque converter solenoid is acting up & not fully releasing, it could load the engne when stopping, kinda like stopping with the tranny in gear, on a straight drive!!!!
Have you tried shifting to "N" when it tries to stall???? If you do & it straightens up, suspect the tranny lock up solenoid.
So try having the computer scanned for codes & let us know all the code numbers they find.
Thread Starter
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Freshman User
Joined: Jul 2002
Posts: 47
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From: Alberta, Canada
Thanks for all the great suggestions!
I'm not having any trouble with the tranny. I was only suggesting that it is difficult to regulate the throttle, step on the brake, and shift into gear simultaneously.
Ok...so here's my list starting tonight...
1. Check trouble codes.
2. Clean and check MAF.
3. Check PCV valve.
4. Fuel filter - has been changed although it seems unlikely.
I'm not having any trouble with the tranny. I was only suggesting that it is difficult to regulate the throttle, step on the brake, and shift into gear simultaneously.
Ok...so here's my list starting tonight...
1. Check trouble codes.
2. Clean and check MAF.
3. Check PCV valve.
4. Fuel filter - has been changed although it seems unlikely.
