Problem with starting

Hey Guys,
I need some ones help. I bought an 87 supra with the intent of fixing it up, but i am stuck with a problem. Whenever i start the car it will idle to 900 then drop to 200 then go back up then down then up and then die out. When I pull the connector of the ISC it does the same but goes to 2000 then dies after going up and down. I replaced the TPS and checked out the isc and it is in good condition along with cleaning out the isc. It also clicks after the car dies. I have fuel pressure. I just changed all three valve cover gaskets but this problem started right before this happened and hasnt ran yet. there are no codes the car is turbo and i have not found an vacuum leaks. Please help!! Thanks any ideas would be great.

If you hear the clicking after shut off the ISC is working, and if you replaced the TPS go ahead and rule that out too. The list is pretty small now but there is one thing on my mind. How do you know it has fuel pressure? Are you absolutely sure it has a few gallons of gas in the tank? Don't laugh, I've done the exact same thing before and couldn't believe my own stupidity. I also had the exact same symptoms even unplugging the TPS and ISC, perfect idle, high idle, low idle, high idle, stall. Either that or something spark related. What happens when you rev it up? Does it stumble or die immediatly?

Im pretty sure I have gas the gauge has always worked. The car always starts and its been doing this for like two weeks. I have an adjustable fuel regulator on on of the lines and its is reading fine as for volume of fuel coming out im not sure. My boost/vacuum guage (aftermarket) is only reading 12 psi vacuum during its short time of idle im not sure if this is because it doesn't have enough time to adjust or there is a leak but i couldn't find one. Head gasket was done a little while ago and torqued correctly. i blocked off the pipe going from the egr to the intake manifold and no change. Could the fuel pump be going? Im not sure if the fuel pressure surges or not. Can the ecu have taken a crap? This all happened suddenly I drove the car and it was perfect except it would occasionally just stall then all the sudden I drove the car with no problems and turned it off then tried to start it again and this happened? Please help anything would be great!

When I rev it up it will go up perfectly fine with no problem and then die like it would if i didn't touch the gas. It doesn't matter how high I rev it it does the same thing.

My car was doing the same thing. It had a really bad Idle. I played with the manual Idle control (Little screw on the intake) and got it to idle correctly. It ran fine for a month and then suddenly quit. It was running fine, but when i went to acclerate it wouldnt gain RPM's and now it wont even start.

-12 PSI or -12 inHG? -12 psi would be a very healthy engine, so it would be fuel or electronics. I don't know of many boost gauges that read in -PSI though. You can definetly rule out the super easy problem of no gas, if it revs up normally then that is not it. What other mods are on the car? Have you pulled the codes also?

Also, I would not touch the idle set screw with the drop of paint on it. If it ran before the problem (and from the factory with the same setting) then the idle adjust is not the problem. Very perplexing problem indeed.

It is 12 Hg I didn't know if that was correct term, but when I tap the gas it goes to its normal before the engine dies out. I do have something new though. The fuel pressure does not stay the same varies with the idle. I do not know if it is supposed to so this because it is an electric fuel pump not based on idle speed. The thing that is differant is that it always used to stay at 40 psi fuel pressure (stock). Now though when I jump the fuel pump to see if it was working it goes up to 60 psi. When the car goes real low in idle the fuel pressure goes down to 20psi. However when the car dies the pressure goes to 60 and drains down to 40 where it stays like it is supposed to for a little bit. Please guys I know Im getting closer to getting my baby back on the road and your help is greatly aprreciated. I have a manual boost controller, larger front mount intercooler, turbo back exhaust, short shifter. I bought the car to fix up but was pretty much lied to about all the upgraded parts. Also the lexus MAF sensor but Im not sure about the injectors (hopefully). but needless to say the car ran before.