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Cylinder 4 misfire even after swapping coils

8K views 12 replies 5 participants last post by  Phear 
#1 ·
As above getting bad misfires under load & P0304 code (misfire cyl 4). Swapped coil pack 4 with 3 still getting P0304 which would suggest coil ok. Any ideas?? 4 new NGK plugs fitted last week. Have checked the large connecting blocks on bulkhead - looked clean & gave em a quick squirt of WD40
 
#4 ·
HT is ok, unless you didn;t actually swap them...did you mark them to be certain you actually swapped them?

if its not spark plug them check the HT lead or the trigger wiring....2 of 4 wires?

TS or JTS engine?

If JTS then the connector to the back of the engine could be defective [ large balck with 24 wires in it. ]
 
#6 ·
Checked compression all between 260 - 280psi, cyl 4 one of the highest. Took out all the plugs - they were blacker than ideal, cleaned them all, replaced in different positions.
The car is still running poorly - very lumpy & misfiring/blowing when put under load (i.e going up hill) however on a gentle downwards slope it revved cleanly through the gears to 5500 rpm. Just done a 10 mile test run but couldn't get any fault codes up despite the misfire.

Any ideas? Just about ready to throw the towel in:mad:
 
#7 ·
#8 ·
Have you checked the exact voltage going to each coil pack at their multiplugs?
 
#9 ·
Is richjts's car still running trouble free? I took that connector apart the other day having read his thread but it all looked spotless so I gave it a squirt of wd40 & put it back together. The frustration with this type of problem is that it can go away for a few 100miles then come back. Lots of threads on here with similar problems but loads of different solutions!

Is a slipped timing belt plausable?
 
#10 ·
been 2 weeks now & the car is still error free :)

he is still smiling like a dog with 2 dicks
 
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