alright so randomly one day when i got into the car started breaking up really bad at WOT or close to WOT and 50% runs fine at any other driving condition it runs perfect no miss nothing. feels almost like the car is running lean. also feels like fuel cut but not as uniform its very random..... so i pulled the plugs they look fine and are all there none are melted or fouled out. put some ngk v powers in. car ran slightly smoother but still breaks up. ran all the gas out went to sunoco and filled up with 100 octane.... car still breaks up. the coil packs look fine its a low mileage motor. i just recently ran lucas injector cleaner. tomorow im going to change the fuel filter... any other suggestions chino rode in the car so he knows how it feels as well. help me out here

 

I'd try swapping out the coil packs, if you could get your hands on som spares. It sounds like an ignition issue.


gadgetSC-t

 

ya sounds like a misfiring or something..ignition related..goodluck

 

What gaps are your plugs try about 28 that should help.

 

i am actually going through the exact same issue with my car and i have had the swap for about 5-6 months. i have changed everything coil packs, igniter pack ,spark plugs,fuel filter, injector cleaner you name it i have done it . the car breaks up every so often but even when it doesn't its not running its full potential you can tell that its still lag's alot . i put a cheap autometer airfuel ratio gaunge and when i hit WOP it it goes to red or no l.e.d light is on so i know that it is lean . i know that is not accurate but it tells you alittle of what is going on . the only two options that i think it might be is the knock sensors i wired up are not correct or the fuel pressure regulator is bad . if that does not work i am all out of ideas. i posted awhile ago on supra forums and nobody really had a answer. i also have heard of the BOV being stuck open and can give you problems but thats all i know sorry i could not be more of help but hopefully we can help each other and get a answer. i thought i was the only person that was having a problem like this because everybody else seems only have little minor or no problems.

 

p.s. only mods i have on my car is a 3inch downpipe and exhaust and a greddy boost cut controller thats it.

 

what coilpacks can i use on the 1j will 2j coilpacks work

 

Yes they will.

 

I would try the coil packs 1st also. try setting your static (no vacuum hose connected)
fuel pressure to 43 psi. do you have a fuel pressure gauge in car? if so make sure its
rising 1:1 w/ boost. If its not rising correctly your FPR is bad or the pump cant keep up.

aureliomk3 - if your going above 12.5-13.0 A/F under boost your going to melt something.

Also try resetting the ecu (pull fuses or disconnect the battery) If I bounce off the rev limiter
too much or just over time driving. The computer learns A/F - toggles between a reg & a
leaner fuel map. the car feels real lazy & not its happy self. The leaner map also seems
to have a more passive timing table making it feel slower. (non technical analagy)
Although w/ the passive timing the car wont spark knock as easily.

 

my car has the stock fpr. if it were the coil packs would there not be a constant miss? the car runs perfect under normal driving and partial throttle. i think i can find a buddy with a supra to borrow a set of coilpacks though and give it a try. ill try resetting the ecu too and ill report back

 

When a coil pack goes bad, you'll have a consistant miss. When they're weak they act
funky. Occasional miss light load & inconsistant. Add boost to the mix, the additional
charge pressure makes the coils work harder. The weak coil will break down only under
boost & misfire. Effectively blowing the flame out. Really a pain to diagnose, unless
you have felt it before. Even then its still a guess till you try it.