hey i got my car back from the tuner today it made 296 rwkw i drove it around for a few hours and it was fine and goes f#kn hard then took it for a strap this arv n its fine until it comes on boost it starts missing and poping sound coming out the screamer it does not miss at the same time sometimes its early in the revs sometimes higher or all the way through but only when on boost any ideas....

ignition or plugs maybe??

the plugs were changed before it went on the dyno but couldve fouled i havnt changed the leads yet can they cause these type of probs,did a search could be the c.a.s but i changed that a few months ago

one of your plugs will be burnt out had this happen to me last month

go back to the tuner

Quote: Originally Posted by Paranoid go back to the tuner ye goin there tmoz hopn i might be able to fix it myself. they were changed before the tune can they burn out that quick

i'm having the same problem usually after 4500 RPM, i took my plugs out and gave them a clean, i think they need replacing tho, try some new plugs and some really good fuel, maybe some octane booster too and don't let the fuel tank get too low, good luck. that's some nice power u got there, would be a lot of fun, i'm hoping for 300 RWKS one day soon.

Quote: Originally Posted by Bigrig one of your plugs will be burnt out had this happen to me last month what about leads

whats your plug gap?

dno just plugs i bought from repco what should the gap be

try regapping the plugs down to 0.8mm

If they give you plugs with a -11 on them, try and get the same part number without the -11 order them in, I think the plug gap on most is .8mm unless otherwise stated (-11 is 1.1). Should get you sorted. And people even gap these down further. What sort of psi are you running, 18 psi or something?

put new plugs and leads its still missing mainly up top running 15 psi what else should i try

What plug gap are they tho? Might need to get some .8's or is that what they are.

Could be a boost cut setup in the ECU by your tuner....take it back to tuner....Boost cut will feel same as an ignition misfire..

theyre 8's

bad fuel?? Tuner may have tuned it right on the line ya know, so all it takes to ping is some lower quality fuel or something

Pinging wont cause a miss...unless its dropped a cylinder from smashing a piston or 2...Lol...that'd be a pretty noticable, permanent miss... We've had to gap plugs down to 0.6 in the past, not ideal....but try that.

i was told might be an electrical prob ,maybe coil or the plugs on the wires that goto the dizzy and coil

this hapened to a mates xr6t when we upped the boost its cause the higher boost blows out the spark.. we regapped the plugs to a lower gap and it fixed it.. try gappoing a little lower..