MISFIRES!! possibly ECU? HELP!!

[bill6639]

i found out something very interesting today,

i swapped my 97 motor into this 96 car and had to use the 96 ECU bc my 97 one was destroyed in the accident

im not 100% on this yet but is the 96 ecu is completely different than a 97

is there a chance that the 96 ecu is the culprit in all my misfire, poorgas mileage, no performance issues??

hopefully some peeps will be able to lmk if my thinking is correct or if im being ********.

god I hope its an ECU and not all my friggin coils

by the way ive been having intermittent misfires on EVERY coil now for a while and as i wait and drive it as it is its been getting worse and worse.

im now getting at best 15MPG
my SES light is on saying my bank 2 cat is below threshhold im guessing bc of all the unburnt fuel cloggin it

my preformance seems to be ok if im on the gas but if im cruisin at like 2K rpm at like high 30's to 40ish itll buck now and then
and if im idling itll misfire like a bastard

ive put in ew motorcraft plugs
ive tried other coils (from 96 motor)
some of the coils seem to help some but still misfires on the cyl just sometimes mor intermittent

 

[79pace]

Have you figured this out by any chance? I dont have any SES lights but the misfires at idle and part throttle sound exactly like my issues and I am getting under 15mpg. The car feels fine when you mash the gas though. LMK if you have figured yours out. Mine is a 97 with the original engine.

 

[Mr Anonymous]

'96 and '97 PCM's are 1000000% interchangeable.

99.9% of the time, misfires are caused by one or more failing/failed coils. Until a coil is completely dead, it will not usually throw a light.

 

[bill6639]

So it's def just a coil issue? if i replaced them all it'd most likely fix the prob. would a single bad coil make others misfire? im seein misses on almost every coil.

 

[79pace]

Mine feels like it is all over the place as well. But the funny thing is that mine goes away for about 50 or 60 miles when I have a full tank of gas.

 

[SHOZ123]

So it's def just a coil issue? if i replaced them all it'd most likely fix the prob. would a single bad coil make others misfire? im seein misses on almost every coil.

The coils share a common 12V+ but are individually grounded by the PCM internal circuits. If the coils were grounded out for more than a few milliseconds at a time it will burn up the coil.

More than likely just bad ones. Especially if they have been handled and have many miles on them.