idles, revs then stumbles

[pukindog]

my 7mgte idles on startup but when you rev it, it stumbles and loses power and returns to idle. this usually begins anywhere between 3000rpm and redline. sometimes when going back to idle t drops way too low and dies. it was fine yesterday and then when i went back to drive it the problems began. also there are no codes.

i have put a new maf on it and i dont see any vaccum lines disconnected causing a leak. put new plugs in as well. when i changed plugs i found the ground for the coil packs was broken but i put a new wire on for that.

what should i check?

 

[BOOSTEDSUPRA]

will it spool up? does it smell like its choking out, or does it pop and crack like its starving for fuel or some sorta ignition problem?

 

[pukindog]

not sure if it spools but its more like it chokes out. its not making any sort of detonation sound. it doesn't make any noise really, just loses power.

 

[nsngarage]

check the resistances on your maf..

if you start it and leave it idle, does it stay idling, or will it eventually die?

 

[CajunKenny]

my 7mgte idles on startup but when you rev it, it stumbles and loses power and returns to idle. this usually begins anywhere between 3000rpm and redline. sometimes when going back to idle t drops way too low and dies. it was fine yesterday and then when i went back to drive it the problems began. also there are no codes.

i have put a new maf on it and i dont see any vaccum lines disconnected causing a leak. put new plugs in as well. when i changed plugs i found the ground for the coil packs was broken but i put a new wire on for that.

what should i check?

Put your AFM back in and try it.

 

[89supra7mgte]

does the check engine light come on when it dies? Had a similar prob with a bad afm. would rev up but soon as you let off throttle it would idle down and die. i noticed that when it would the check engine light would come as if you had just turned the key but would go out soon as restarted. Pop your jumper in there soon as it dies and see if you get anything?

For some reason mine would not set the afm as a hard code. i did the tests on it and it checked fine but kept settin the afm code when it would die. replaced it and problem gone.

 

[CajunKenny]

The check engine light always comes on when it's about to die and after it dies. Nothing to note there.

Sounds like a vac/boost leak to me. Did you reconnect the vac line on the bottom of the accordian hose?

 

[pukindog]

well here is the issue, the problem occured on two different afm. it idles and stays idling until i cut it off. when i unplugged the afm and tried to rev up it immediately died so im pretty sure that is not the problem. although, i unplugged the tps and the exact same problem persists, so i believe the tps is faulty. and yes i plugged in the vaccum line in the bottom of the accordian. when i got the car that one and the bypass valve port were both open but it still ran fine.

how would i check the tps to be sure? and the afm as well. it cant hurt.

 

[89supra7mgte]

I know the light comes on like that. I was just stating in my case i decided to throw my jumper on and see what was there and it would have that code, soon as started with jumper in code was gone? i had cleared code out to rule out history code as well. Maybe i just got lucky?

 

[CajunKenny]

Oh, I gotcha. You had TE1 and E1 shorted to try and catch what code it was throwing right as it died. I'm with ya now.

OP: Here's the check out for the TPS.

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=101

 

[89supra7mgte]

EXACTLY, and it worked, like i said soon as i would restart the car code was gone even without me clearing.