I have a 2000 F150 and wondering if a coil pack is going bad. How do I diagnose? I get an intermittant rough idle. I cleaned the throttle and Motor Control Valve and ran fuel cleaner.

Jeff

 

i'm in the same boat. Replacing for the sake of replacing isn't cost effective.

 

Have you tried checking with the dealer? I've got a 2001 and had a rough idle problem too.. very noticeable when in gear and stopped at a red light or something.

They did a software upgrade on my computer and the problem went away.

Some bright guy at Ford didn't care to take into account that if the batter is disconnected or goes dead.. you just reset the computer back to fatory settings.. meaning no more software upgrade and my problem came back again. They need to use a memory type that stores the software changes despite losing power.

 

Not sure I understand what you're saying here. The PCM program is not stored in RAM that is erased when power is removed. I believe its installed in a EEPROM type device which retains memory when power is removed.

 

Clean the MAF sensor, unless your rough idle is some really serious problem. That actually worked for me.

 

MAFS is one to clean, the other thing to look at is the IAC, these seems to have problems getting crapped up, and causing idle problems for some.

LMC cleaned his awhile back, and it stil is fone after 12 to 14 months if memory serves me correctly.

If you want to try a search on this use IAC* as the term.

Let us know what happens with it, what you try and what worked.

 

when a coil pack is bad you will have a severe miss when giving throttle. it will be hard to distinguish while at idle. Also you will get a code and when you read the code on a scanner it will be a engine misfire cyl x (fill x with cylinder coil pack thats bad)

 

Perhaps they are using EPROM to store the main program. All I know is.. I take my truck to the shop and explain that its got a shake while idling. He upgrades my computer software and the problem is gone... life is good. MY airbags get stolen (battery is disconnected to prevent airbag blowing up in theif's face.. smart theif). Thus my computer is reset and the problem with rough idle returns.

This indicates to me that if the computer is reset... all changes to software program are reset as well. If ALL of the program is burned into the EPROM it should still have stored the software changes as well as the original program.

I'm not trying to argue with you... just stating my ASSUMPTION.

 

Not an expert on the Ford computer system, However it is possible to load a program into systems and not burn it to the eeprom. That may be why you lost the upgrade. just a theory