what would cause my 2002 ford explorer to miss while at an idle

2002 FORD EXPLORER
136,639 MILES
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ML5888
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Car runs great no service engine light is on, just at in idle the car misses at idle. Just had the timing chains replaced. the Garage that replaced the timing chain said that cyclinder 5 was misfiring, changed spark plugs and wires
Nov 10, 2011 at 12:30 AM
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ASEMASTER6371
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it could be running to lean causing a lean missfire.

how does it run off idle?? did the chains and tune up resolve your problem??

Roy
Nov 10, 2011 at 12:36 AM
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ML5888
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runs good off idle the chains and tune up did not resolve the problem, am thinking maybe the coil pack is bad have been told that fords go thru them
Nov 10, 2011 at 12:41 AM
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ASEMASTER6371
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yes they do, common failure.

you had the chains and tune up done for this missfire??

is the shop helping you out from there miss diagnosis??

Roy
Nov 10, 2011 at 12:44 AM
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ML5888
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no done the chains first then the garage found the misfire on cyclinder 5 then they changed plugs with no resolution to the problem, i changed the wires the same day the plugs were changed, the garage was just throwing parts on it and not really trying to fix the problem. The reason the timing chains were done was you could hear them rattle and they said after they replaced the chains that it was giving a cyclnder 5 misfire. I have drove this vehicle several times since the chains were replaced and have not had a check enginge or service engine soon light come on. Like I said it only does it on idle while stopped, rpms around 100 to 300 rpms at idle
Nov 10, 2011 at 12:52 AM
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ASEMASTER6371
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ok, first, the idle is too low and may be the issue. the idle air control motor on the top may not be working as the idle needs to be 650-750 rpm.

did the shop do a compression test?? it would have been a good start to make sure the motor is in good shape.

a vacuum leak or dirty throttle body may be an issue too.

Roy
Nov 10, 2011 at 1:09 AM
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ML5888
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Do not know if the shop did a compression test, all i know is that they replaced the plugs said they were gapped to far so that is why i was thinking coil pac, or maybe the IAC is not operating or the MAF needs cleaned where should i start
Nov 10, 2011 at 1:53 AM
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ASEMASTER6371
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the iac motor is a good start. it is not the mass air flow.

clean the throttle body as well.

Roy
Nov 10, 2011 at 2:05 AM
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ML5888
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What would be a good cleaner to use and i will pos tto let you know if it fixed the problem
Nov 10, 2011 at 2:15 AM
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ASEMASTER6371
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3 m makes a good cleaner available at any parts store.

Roy
Nov 10, 2011 at 2:21 AM
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ML5888
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another question if i had a valve bad would i not feel it miss while i drove it or just in the idle? Will go tomorrow and pick up the cleaner and see if that works thanks you have been a great help
Nov 10, 2011 at 2:28 AM
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CJ MEDEVAC
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BEEN FOLLOWING YA'LL

I DON'T KNOW HOW HARSH THIS WOULD BE ON THE IAC (I'M A CARB KINDA GUY)

AS FAR AS THE THROTTLE BODY GOES---YOU WILL NOT FIND A BETTER AEROSOL CARB CLEANER THAN "VALUECRAFT" AVAILABLE AT AUTO ZONE

I SOMETIMES DEMONSTRATE TO OTHERS, HOW "VC" SPRAYED ON FOR 30 SECONDS THEN SPRAYED AGAIN.......WILL CLEAN BETTER THAN USING THE WHOLE CAN OF A COMPETITOR!

JUST TRYING TO GET YOU THE BEST BANG FOR THE BUCK!-----I HAVE USED 'EM ALL OVER THE YEARS......I CAN MAKE A CAN OF VALUECRAFT CLEAN A WHOLE LOT!

ASEMaster6371 I'LL LET YOU SUGGEST IF IT'S OK FOR THE IAC

THE MEDIC
Nov 10, 2011 at 2:33 AM