I am having this intermittent issue with breakup when coming into full boost. And I say intermittent because I could go out and it will pull good and then later that day it will start the breaking up issue again. My problem comes randomly and leaves randomly. Two days ago I did a 3rd gear pull with no problems, then right after I did a 2nd-3rd gear pull and had a lot of breakup. Then did a 3rd gear pull again and it was clean, no breakup. Then just yesterday after lunch I did some 36psi pulls in 2nd, 3rd, and a little of 4th. Car pulled wonderfully. Later in the afternoon I go out and roll into 3rd gear and as soon as I am coming into full boost it started breaking up and popping. Tried a couple more times and the breakup continued.

I have tried new plugs, regapped plugs, checked grounds. I have done PLENTY of searching on the forums. But it seems that everything I find is a consistent problem for people and not intermittent like mine.

Evo IX
aem ems v2
sparktech non-cdi pro ignition (sequential system for AEM EMS)
stock ix plugs gapped at .018 right now (.020 was breaking up as well)

I have read a lot about cam position sensor gong bad and causing breakup, but again, those people are having the issues consistently.

Any input is appreciated. Thank you.

First, you shouldn't need such a tight gap with the COP, I would open spark plug gap to .020-.022.


Are you on MAF or speed density?

If I had a "Built, 6466, 924whp" I would not run stock range plugs.

Speed density.

Plugs were gapped at .020 when the issue started. My tuner told me to close the gap and try but no luck

It made 924 back in the day. I am now on a full flex fuel tune done by Lucas English. He is the one telling me to use stock heat range plugs.

And if heat range or gap in plugs is the issue, it wouldn't make a good pull one day and then have breakup the next. Same gas. Nothing changed.

Have you tried changing in some known good coils? When the coils were starting to go in my car, misfires were intermittent at first.

No I have not. There is only one other evo around my area that has a COP system and he is on stock ecu. My AEM and wiring is currently setup for 4 channel sequential ignition. I wouldn't think it would be that easy just to swap over to his ignition. Correct me if I am wrong.

As long as his coils use the same plug it should be extremely simple to just swap the coils out.

no, checked with my tuner. he would need to change my map up

To unplug coils and plug in different ones? Are your coils hardwired to the car? You're not changing the whole ignition system and wiring. Just the coil, right at the spark plug..

I am using a sequential system (4 channel system) tuned on an AEM EMS. The system I have access to is non-sequential (2 channel system like stock). my map would need adjusting to fire that ignition system correctly.

tuner said it would be a pain and would require modifying my map

I see what you are saying though, just change the actual coil itself. but my friend is actually using Honda k-series coils...doubt things would work right

They're all denso coils. See if the plug is the same, it should be. You can definitely swap just coil, leaving the current wiring in place and it won't affect anything..

my friend has 3 wire coils...mine are 4 wire