My 88 supra turbo sounds like its dieing. Just recently it has started acting up and it has gotten progressively worse. When first started cold its good, but once starting to warm up and the rpms begin to drop the idle gets extremly rough and fluctuates between 450-550 rpms constantly (sounds like every second someone blips the throttle). It doesnt stall but comes damn close because the check engine light comes on for a split second when the rpms hit low enough. The vaccum often fluctuates with the rpms as well or other times it will just lower to around 10-12 and sit there. If i drive it or let it idle long enough to completly warm up the idle steadies out to around 650 rpm and the vaccum goes up to about 19. I have tried unplugging and plugging the tps back in and it seems to almost be better when the tps is unplugged... not by much but maybe a bit. My isc does make the clicking noise. I have no fuel mods just intake and exhaust. Please help... i cant stand to see her like this.
PLEASE HELP! it sounds like my babys dieing...
- Thread starter 88SupraTurbo
- Start date
My 87 turbo had the same problem when i got it. I removed the ISC valve and cleaned it and it fixed it. (had to do some minor adjusting on the idle screw and stop screw). Also if you have the time pull the 3000 pipe off and clean the carbon deposits from the TB. Hope this fixes your problem like it did mine. Good Luck
88SupraTurbo said:
Shameless Plug :naughty:
I've got a cleaned/refurbished ISC with a chrome ceramic base/flange for sell in the FS section. $40 shipped.
If those other things don't work I would check out your Throttle Position Sensor. When I put my new engine in my car did the same thing except it would fluctuate from like 2500 to 3000 rpms.
the stop screw is at the end of the throttle linkage close to driver side fender. The Idle screw is in the little piece on the Intake manifold that sticks out toward the front of the car. Might have a black rubber piece covering it. A flat head screwdriver is all you need for both of them, you may not have to adjust them, I did because i messed with the idle before cleaning the ISC valve. I cleaned mine with soft tooth brush and carb cleaner. Oh and others said if this doesn't help your problem then the ISC may be bad (autozone can test them for free) then I would check back at the TPS. A new ISC will run between $350-$400. I have an extra ISC in working condition that I bought incase mine was bad but after cleaning mine worked mine. You can have it for $25 shipped. I would clean your existing one though 9 times out of 10 it's just needs to be cleaned. Good luck again.