Idle Fun...
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Junior Member
Joined: Nov 2009
Posts: 11
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Idle Fun...
Hey,
So I've been having a little trouble with the idle in my truck lately. 1991 f150 5.0 auto. It has trouble idling and will die sometimes if i do not give it some gas for a for a while when I start it up. Other times it just likes to surge pretty badly. The previous owner took the gas tank vent/carbon filter and plugged it before the purge solenoid on the solenoid side.
I ran the codes and got 31, 332, 344 and 628. I'm guessing it's something to to with the emissions system but what? Could this be my o2 sensor? I took the little green hose off the EVP and blew through it and very little air came through could this be the problem? I guess i should get a multimeter and start testing sensor voltages?
What should I look at first?
TIA
So I've been having a little trouble with the idle in my truck lately. 1991 f150 5.0 auto. It has trouble idling and will die sometimes if i do not give it some gas for a for a while when I start it up. Other times it just likes to surge pretty badly. The previous owner took the gas tank vent/carbon filter and plugged it before the purge solenoid on the solenoid side.
I ran the codes and got 31, 332, 344 and 628. I'm guessing it's something to to with the emissions system but what? Could this be my o2 sensor? I took the little green hose off the EVP and blew through it and very little air came through could this be the problem? I guess i should get a multimeter and start testing sensor voltages?
What should I look at first?
TIA
Junior Member
Joined: Aug 2010
Posts: 20
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just cleaned my 92 f150 throttle body removed and cleaned the back side with a small wire brush and carb cleaner this is where you may find your problem gunk buildup mine had never been cleaned 20 years of gunk can change the TPS /computer ect reading the throttle position etc. ... this solved my idol problem its running better than ever
Junior Member
Joined: Jul 2010
Posts: 23
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codes
http://fordfuelinjection.com/?p=14 Try this link for the codes.
I do not know what year Ford started coating the inside and parts of the throttle body with Teflon but a '93 (example) has a warning label on it to never clean the throttle body. However you can clean it but do not use carb or injector cleaner etc. Use only Throttle Body Cleaner or you may have sticking idle problem afterward. Toothbrush or a rag on your finger is best.
Also look at the EVR solenoid to make sure it is working correctly. It works on a signal from the pcm and passes vacuum to the EGR valve when the engine is warm enough. The EGR valve psoition sensor feedback to the PCM. The solenoid on a '93 is mounted on the drivers side of the engine on top of the valve cover toward the rear. Mine has a pair of them. I think it is the front one but not 100% sure wihtout tracing out the vacuum lines. A Haynes manual is well worth the cost.
I do not know what year Ford started coating the inside and parts of the throttle body with Teflon but a '93 (example) has a warning label on it to never clean the throttle body. However you can clean it but do not use carb or injector cleaner etc. Use only Throttle Body Cleaner or you may have sticking idle problem afterward. Toothbrush or a rag on your finger is best.
Also look at the EVR solenoid to make sure it is working correctly. It works on a signal from the pcm and passes vacuum to the EGR valve when the engine is warm enough. The EGR valve psoition sensor feedback to the PCM. The solenoid on a '93 is mounted on the drivers side of the engine on top of the valve cover toward the rear. Mine has a pair of them. I think it is the front one but not 100% sure wihtout tracing out the vacuum lines. A Haynes manual is well worth the cost.
Last edited by c.j.; Aug 19, 2010 at 10:02 PM. Reason: more data
WOOF
Joined: Feb 2010
Posts: 790
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From: San Antonio, TX
IAC is a good start. last tune up? and try this- https://www.f150forum.com/f33/how-se...-1991-a-31505/