3sgte gt4 missing badly.. any ideas?

[danny2]

hey guys

my car is a 90 aus spec gt4,

I'm having a jerking problem at about 2grand till boost not all the time but most, the car misses badly but when revs pick up is fine .. it has new leads and iridium plugs and fuel filter, so those can be ruled out .. it idles ok, not the best, i've also checked for vacuum leaks but miss is too violent for a small leak, i'm going to change the fuel pump soon as well

any idea?.. anyone had similar issues??

thanks

[Dale]

injectors been cleaned? Could have an air leak in one of them too causing the miss

Take the injector rail out and get them tested/cleaned somewhere

[thechuckster]

short the timing test pin to earth in the diagnostic port and see what timing you have at idle?

[Jorrs]

sounds like the same symptoms when my TPS was buggered, was jerky at low revs as the injectors would cut out, so had to keep the revs high to drive it.

[tooch]

AFM is another thing to look at. Check the wiring, check if it's full of oil (it will be ).

[BeRad]

or check that the plug is plugged in

[danny2]

thanks for your ideas guys.. i'll look into it soon and keep you posted

cheers

[mikie_121]

car won't run without afm, i tried that the other day it stalls instantly when it's unplugged ( i wanted to ditch the restrictive afm ).
how's the dizzy? and what is the ignition timing set at?
also try taking out the air filter and see if that makes a difference.
but problem is most likely electrical like wrong ignition timing or leaky vacuum hose to dizzy.

[camrygt?]

my 205 3sgte became a real pain when the 02 sensor died, under light throttle it would go into closed loop and run crazy, full throttle and boost it ran fine. Not sure how much effect the o2 sensor has on the gen2 but maybe try unplugging it and see if that makes a difference

[Joshstix]

Have you done a compression test?

[danny2]

no i havn't done a compression test.. whats a normal psi range for a 3sgte? and where is the fuel pump fuse?

[Joshstix]

Not too sure on either of those questions but all I'd be looking for is consistency. If one pot is down on compression you'll get the behaviour you're describing. Don't ask how I know