Maf

[sean210]

The other day I went out to start my car and it would rev to about 1300 and
then drop to 250 and then jump back up to 1300. I started unplugging sensors
and nothing changed then I unplugged the MAF and it would idle.
Would that mean that the MAF is bad?

 

[st2b]

The Supra is NEVER going to run if you un-plug the Mass Air Flow sensor plug. In fact, you probably have a vac leak, or something along that line. Check the vac lines, plug wires, Throttle Position Sensor (On the throttle body) and be sure you have everything connected right.

Did this just happen out of nowhere? Like what did you do before it started acting up like this?

 

[Finnon]

poss leak in pcv system i should imagine

 

[sean210]

The Supra is NEVER going to run if you un-plug the Mass Air Flow sensor plug. In fact, you probably have a vac leak, or something along that line. Check the vac lines, plug wires, Throttle Position Sensor (On the throttle body) and be sure you have everything connected right.

Did this just happen out of nowhere? Like what did you do before it started acting up like this?

It runs and drives with the MAF unplugged. But if I plug it back in it wont run.

It never did this just started out of now where. I changed my valve cover gaskets and it ran just fine for a week and then did this.

 

[st2b]

poss leak in pcv system i should imagine

Here's your problem

 

[Nalleywhacker]

sounds like tps to me. i changed my turbo out a while back and never touched the tps and some how it got screwed up it was jumping from about 500rpm to about 2000rpm and i had to recalibrate it. idk might be your pvc, my case was the tps.

 

[CRE]

st2b is dead right. There is NO WAY a stock N/A will run with the VAF disconnected... If that is indeed the case I suggest you start working on getting the wiring back to stock first. Checking for vacuum leaks, calibrating the TPS and checking out the ISC aren't bad ideas, but I would start with the VAF's harness.

 

[sean210]

Now I am confused. I am being told that my car will not run with the MAF
unplugged. But the only way i got the car home was to unplug it and drive it.

Has my car been damned by satan or what?

 

[CRE]

No, you've either got a short in your VAF's harness OR the fuel pump's been rewired (and VERY poorly by the sound of it).