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Discussion Starter · #1 ·
Hello
My 94 Supra sputters and sometimes backfires when i boost in second gear. Sometimes in first as well. Sometimes it does and sometimes it doesnt. If iam at stock boost its fine. But once i crank it up a lil bit it does it again. It never did this before when i used to boost 20psi. It started recently. I had NGK 3330 but i changed them and it still does. I have the HKS EVC IV controller. What could be the problem? Thanks
 

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BLiTZ Supra TT said:
I put in Fuel Injector cleaner because it was already doing that. But it didnt work.
Fuel Injector cleaner does not always do a good of a job as you would think. Try gapping your NGKs down a bit, they come at .0325 and some people may need less gap. You might want to look into having your injectors professionally cleaned and balanced by RC Engineering, they are in California. If you have a high milage supra that may be your problem.

-m
 
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Discussion Starter · #5 ·
HI, YEAH MY CAR IS DOING THE SAME, I DUNNO WHAT THE PROBLEM IS, I CHANGED THE PLUGS TO DENSO AND GAP THEM AT .30 AND IT WAS FINE FOR AWHILE BOOSTING 1.2 BUT THENALL OF A SUDDEN I CRANK IT TO 1.3 And BHAM!!! it did it again on the freeway..any help? please!!!
 
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Discussion Starter · #6 ·
How many miles do you guys have on your cars?

Hint: the stock coils deteriorate over time. Not sure what it is, but they definitely do. A little story:

I got my car stock at 21K miles, and BPUed after a few months. I ran stock plugs at stock gap, no problems. After a couple months, it started missing. First minor, but progressively worse. I ended up having to gap down NGKs to .028 before it would clear! After making a lot more power later, I had to gap down more and more. In the end, I was to .022. I put new coils on, and WOW. I noticed an immediate difference. Gapped up to .026 and still no problems, at 2.0 bar + NOS. They can probably go higher, I just haven't bothered taking them out to try.

I think either the spring wears out and doesn't provide as good of contact, or the coils get heat-killed. Either way, gap down or change your coils.
 
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