leesfer

Hey guys, I've got a 2001 AP1 and I've got a misfire in cylinder four but sometimes it becomes a random misfire in all cylinders

It feels like I am running on three cylinders with a major loss in power... but it still idles, revs, and hits vtec fine

First thing I did was change the spark plugs, but the plugs I pulled out looked okay still

Then I did a compression check which showed good compression (225 in every cylinder except for 1 which was 210)

I pulled the valve cover off and did a valve adjustment since my car is about to hit 90k miles and while that was off I did a leak down test but everything was good there with only 20% leak in every cylinder

Anyone have any other ideas or things I should check for?

I don't know where to go next

BBV S2K

Coils? or coils connection?

I did a compression test and got

1-210
2-215
3-210
4-220

franky

swap #4 coil to a different cylinder and see if it still misfire. if no misfire in #4, then its the coil. if theres still misfire in clyinder 4, then it's either spark plug or injector.

leesfer

Did this already and still a misfire in cylinder 4

Already changed the spark plugs so it must be the injector

yomny

keep us posted, i have random misfires and misfire CEL on all four cylinders. I'm starting with a valve adjustment and spark plug change.

rob-2

Is the connection to the coil pack good?

leesfer

I assume it is, I have removed and rotated the coil packs multiple times now and torqued them down to spec

twohoos

Had a similar issue a couple years back on my MY00. In my case, both the coil packs AND the ECM were fried. Took forever to diagnose - I couldn't believe it could be both. But eventually, back-to-back testing with known-good coil packs and a known-good ECM proved that the misfire would recur when either one of the parts were swapped, but not both. My assumption (admittedly never proven) is that there's enough electrical feedback btw ECM and coil packs that as one started to degrade, the other was eventually damaged as well.

Just a thought. Good luck.

leesfer

here's an update:

Finally had my injectors taken to be cleaned and checked, but turns out they are still perfect after 10 years

Shit. I was hoping that was the problem.

I am going to double check the coils now

_brandon

-coil tester (or the dangerous way of put the plug against a ground and starting the engine to see the spark)
-comp test
-Take your injectors to a shop and have them tested
-Check the connection to the fuel injectors (zip tie the connection just to be sure they arent loose)

should find the problem.. I had two coil packs go out on me at christmas.. Took me forever to find out that both had failed and not just one ffs..