Subject: mitsubishi 3000GT VR4 twin turbo intercoooler
Question:

Hello, I have a Mitsubishi 3000gt VR4 twin turbo model 91 my problem began after a 1/4 mile race my RPM went down to 0.1 or turn off but when I feed it the gas and the turbos start ,the problem disapear, I check the presion of the gas and it´s ok .sometimes the problems disapear but when i turn the engine off for 5 minutes and then start again the problems start over again
I lost the power of my car in low RPM, only when the turbos works disapear
I have changed the gas filter ,air filter and I install a bigger intercooler for the race ,the sparkplugs are fine
some people thinks the problem is in the injertors. but why works fine in hi rpm ?
If I push the gas in neutro the turbo marks only the half of the presion or less ,my engine is standard and dont have more modifications
Please help me thank you
Sorry for my writting
Answer: Benjamine,
Check your air hoses that connect from your turbos to your intercooler. If there is an air leak present, your RPMs will be below normal at idle. Also, when you install a larger intercooler, that will allow signifigantly more air into your engine. When your car's computer detects all that extra air entering your engine, it will either try to inject more fuel or lower your idle to slow down the air flow. Too much air entering your engine can cause detenation, which is very bad for your engine. The reason why your engine seems fine when you step on the gas is because your car's computer gets a signal that the throttle plate is no longer closed, and starts increasing the amount of gasoline entering your engine. When you engine gets more gas, it can then also receive more air, and your engine will appear to be running fine.

Simply adding a new intercooler for extra power is usually not the best method for upgrades. It can cause extra strain on your fuel pump, fuel injectors, and fuel pressure regulator. With a larger intercooler, more fuel needs to be supplied. Depending on the size of your intercooler, you may need to upgrade your fuel injectors, fuel pump, fuel pressure regulator, and sometimes even a secondary air/fuel management computer to assist your own car's computer.

If you can, install the old original intercooler back on your car and see if the problem goes away.
Good luck!