'97 4.6 coils

boomyal · #1 (**permalink**) 01-12-2008, 07:13 PM

What is the likelyhood that both of my coil packs have weakened? It is a heavily loaded, but tenderly driven '97 E150 with 230k miles on it. The OEM plugs have 30k miles as well as a new set of plug wires.

My issue started out under minor loads, in OD. I would kick out the OD and the cutouts would quit. As time went on, kicking out the OD would only diminish the the cutouts but in all cases, regardless of the frequency, they were momentary but signifigant. This never happens at surface street speeds, only at highway speeds.

I determined that I had a coil problem so I bought one and flipped a coin as to which side to replace. Once done, the problem is greatly dimished but not eliminated.

Now I'm thinking that both of the coils had been breaking down at the same time.

Is this likely? I'd hate to go buy another $65 coil just to find out they were not the problem.

tjc transport · #2 (**permalink**) 01-12-2008, 08:54 PM

have the vehicle scanned for trouble codes. they will tell you which cylinder or cylinders are experiencing the misfire condition.

boomyal · #3 (**permalink**) 01-13-2008, 12:20 AM

Quote:

Originally Posted by tjc transport

have the vehicle scanned for trouble codes. they will tell you which cylinder or cylinders are experiencing the misfire condition.

Thanks tjc. I have had plugs misfire in the past, specifically when they reached the end of their useful life, ie 90 to 102k miles. After a few misfires (very nominal in their symptoms) the check engine light would come on. The resultant codes would reveal the cylinder that was misfiring.

In my current, now protracted experience, no check engine light has been displayed. I did ask a local mechanic and he indicated that without the warning lite, there would be no codes to retrieve.

Am I missing something?

tjc transport · #4 (**permalink**) 01-13-2008, 11:03 AM

you can have a cylinder misfire code stored in the computer without a cel coming on. the cel will only come on if it is a constant miss, or a dead cylinder.

an occasional miss will produce a code, but not a light.

i just explained this to my nephew yesterday. his 02 5.4 had a flutter and bad stink from the exhaust.

he brought it by, and i instantly heard an occasional dead miss in the exhaust. i put the scanner on it, and got a 308 code, misfire#8 cylinder. he could not understand it, cause he did not get a cel come on. we changer #8 coil, and the miss went away.