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So my car was missing under boost...I tried second hand yellowjackets and new plugs at 0.8... Still misses...

Then I do a turbo upgrade with pretty much everything new.. Both manifolds, injectors PFC fuel pump etc.... Still misses...

Today I went and bought new splitfires and put em in...miss got worse.... Now it's like really loud backfiring... Different to before.

Has anyone got any ideas to help me solve this problem.

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Youve added a shit load of stuff to the equation now....should have sorted it before the upgrade, but still check CAS and make sure the blue plug on the ecu is in evenly, pressing in the ends and not over tightening the 10mm bolt, And I assume u changed the afm to Z32?

When you say backfire, on accel or decel?

Yeah it's missing on accel and sounds almost like a rev limiter with lots of little backfires..

Yeah it's a z32 afm and Toshi tuned it, we did what we could but we stopped when it was missing and I was going to go back and finish the tune once it's fixed.

Try gapping down your plugs to 0.6-0.65. I just did that and sorted my cutting problem at 0.8 Bar. Now good all the way to 1.4 Bar. I think my coils are loosing power so confirms that it is spark related.

Running that gap now with no probs at all, until the shop warms up to re-mount my coils (I run bosch coil set-up).

Dont think its actually the coils..For reference my splitfires had enough juice to run a gtx30 @20psi with wmi and 1.1mm gap

Sounds like an electrical gremlin....As said before check coil pack loom, ignitor if you have one, also make sure all earthing on the engine and batt terminals are clean and tight and again CAS

What plugs you running?

So if you get mad backfiring an high in the rev range it could be leaning out coz of the pump?

Definitely, mine did the same thing today on the dyno, changed coils, gapped plugs, no change. Ended up being one of the pos Walbro 342's not pumping properly. It seems they need to be fully submerged to operate at maximum flow, unless its just faulty... I was hoping the deatschwerks didn't have the same design flaw as this fault was occurring at 1/3 tank.

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