changing idle
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changing idle
I have a 1994 Ford F-150 302 EFI v8 truck with a changing idle problem. The idle will go from low idle that is kind of rough to a normal idle and sometimes a high idle. WHen its in a high idle it seems to drive it self and when its in low idle and i touch the gas it switches to a high idle. I ran the KOER Test and it said that it couldnt control the high or low rpm's. The check engine light comes every so often but it doesnt seem to run any different when the light is on. I took it in and they said they coulndt find nethign wrong with it. I dunno. Please help.
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simular problem
Hi yall,
I have a like problem, with the exception of the brakes work fine, firm pedal all the time. MIL light comes on during driving with no detectable change of driving condition or perf. Idle will be be normal then get rough, then idle up for a few seconds then back to normal, and start over again. almost like a cycle trying to correct itself or compinsate? My truck is the 5.8, not sure if this applies, but I found the 'canister purge valve' (-looks like a windshield washer pump with 2 vacuum lines going to TB, its located near TB) to have one side broken off. I bypassed it to see if changed and now it will idle normal until it warms up then it will go back to the loopy idle.
Also it has a slight EM leak.
I'll check codes this weekend and post back.
I have a like problem, with the exception of the brakes work fine, firm pedal all the time. MIL light comes on during driving with no detectable change of driving condition or perf. Idle will be be normal then get rough, then idle up for a few seconds then back to normal, and start over again. almost like a cycle trying to correct itself or compinsate? My truck is the 5.8, not sure if this applies, but I found the 'canister purge valve' (-looks like a windshield washer pump with 2 vacuum lines going to TB, its located near TB) to have one side broken off. I bypassed it to see if changed and now it will idle normal until it warms up then it will go back to the loopy idle.
Also it has a slight EM leak.
I'll check codes this weekend and post back.
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well i put the booster in and now the brakes work great but it still has the changing idle problem. I tested the IAC and thats fine but when i tested the TPS i couldnt get nethign to read. Maybe thats my problem.I just dunno.
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checking tps
I have a mist in the engine and checked my Tps all so
coundnt get a reading make sure you have it on ohms.
The idle air control (IAC) is how you ajust the idle on the engine it sends the single to the TPS theirs an ajustment on the top side of it. Has anyone had the problem of a mist in the engine at idle I can't find it need help.
coundnt get a reading make sure you have it on ohms.
The idle air control (IAC) is how you ajust the idle on the engine it sends the single to the TPS theirs an ajustment on the top side of it. Has anyone had the problem of a mist in the engine at idle I can't find it need help.
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From: Michigan
I had the same problem 1990 F250 5.8L. I tune up the engine for about 150 dollars that did no good. So i check all sensors when i got to the TPS sensor I found it reading low about .48 to .6 volts with key on engine off I replaced the TPS sensor now the truck runs like new.
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well i did the koeo test and i got a continuous memory code of 327- EVP or DPFE circuit below minimum voltage. I dunno what this means i tested the EVP and thats alright but how do i test the DPFE and where is it? Also, when im turning or the A/C kicks in the engine will change to its higher idle. I dunno maybe this has to do with the IAC maybe opening to much as it adjusts for the more load when its idling or something. tellme what u thinnk please.
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problem with Idle
Only thing that I could find is EVP,the DPFE is a circut the manual
said either. The EVP works with the EGR. Check the TPS on the rough Idle. The A/C has a Idle control also.
said either. The EVP works with the EGR. Check the TPS on the rough Idle. The A/C has a Idle control also.
Last edited by sapp95; Apr 4, 2005 at 06:21 PM. Reason: left part of answer
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Well i think i found it/ Im gonna go get the part tomorrow. I was running the koeo test agian and nothing new came up but i noticed this like clicking noise coming from the engine. So i got up in there and found out its one of the Idle air bypass solenoids up bye the coil and fuel pressure regulator. I let ya know what that does.