rough idle
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rough idle
I have a 92 f150 xlt 4.9l and it has a rough idle. I will say that the truck has sat for the past 10 or 15 years.Now that I have it I've been trying to drive it and work out some kinks. I think its either the fuel pump or the iac, but I read some where to check the iac is to unplug it while the truck is running and it should cut off, so I tried it and the truck did cut off almost immediately and I'm guessing that means the iac is good. Part of the reason why I suspect the fuel pump because the front fuel pump doesn't work and I think there was fuel in the tank that has sat up and gunked everything up.
Tonight I did put some lucas fuel injector cleaner and let the truck idle for about 10 min. At first it seemed to be working but after awhile I noticed the idle getting worse to the point where it almost cut off. When that happened I rev'ed it up to 1k and held it there and it was still running rough. Can I get some help?
Tonight I did put some lucas fuel injector cleaner and let the truck idle for about 10 min. At first it seemed to be working but after awhile I noticed the idle getting worse to the point where it almost cut off. When that happened I rev'ed it up to 1k and held it there and it was still running rough. Can I get some help?
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Joined: May 2010
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Probably a good idea to check, or better yet replace, the fuel filter if you haven't yet.
If that seems to help you might want to get an extra one. If the truck sat that long it will probably plug up a filter fairly quickly. You may end up replacing the tanks and pumps. Probably will, but you might get lucky and get by with a filter change or two.
If that seems to help you might want to get an extra one. If the truck sat that long it will probably plug up a filter fairly quickly. You may end up replacing the tanks and pumps. Probably will, but you might get lucky and get by with a filter change or two.
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Joined: Oct 2010
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From: Charleston SC
OK that seems like an overly excessive amount of codes. I think you may need to start looking into an ECM problem. Yours appears to be a 3 digit format, your first code should be a 111. Which is a system pass code which you did not get. So this is what I get from the codes and please, anyone reading this, feel free to correct me...
117 - ECT sensor circuit grounded
638 - TOT sensor circuit below minimum voltage
126 - BP or MAP sensor higher or lower than expected
122 - TP sensor circuit below minimum voltage
112 - ACT sensor circuit grounded or reads 254 degrees F
327 - EVP or DPFE circuit below minimum voltage
654 - MLP sensor not in park position
513 - Failure in EEC processor internal voltage
552 - Air management 1 circuit failure
556 - Fuel pump primary circuit failure
The last code I saw was a 52. I do not know if that was the ECM's attempt at a legitimate code or if that was the code for the cylinder balance test. Just so's you know, a code 52 in 2 digit format means power steering pressure switch circuit opened.
117 - ECT sensor circuit grounded
638 - TOT sensor circuit below minimum voltage
126 - BP or MAP sensor higher or lower than expected
122 - TP sensor circuit below minimum voltage
112 - ACT sensor circuit grounded or reads 254 degrees F
327 - EVP or DPFE circuit below minimum voltage
654 - MLP sensor not in park position
513 - Failure in EEC processor internal voltage
552 - Air management 1 circuit failure
556 - Fuel pump primary circuit failure
The last code I saw was a 52. I do not know if that was the ECM's attempt at a legitimate code or if that was the code for the cylinder balance test. Just so's you know, a code 52 in 2 digit format means power steering pressure switch circuit opened.
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