I recently tuned up my 1.8L Celica ( cap and rotor, spark plugs, air filter, fuel pump ), however after driving it for about 10+ miles or so, the RPM will suddenly fluctuate rapidly and my car will stall. It starts up again, but the same symptoms occur and my car stalls again. I let the engine cool for about an hour or so, then it starts up and runs again. I'm not sure what is happening. Could it be the the ignition coil? My in-law who is a mechanic said it could be the distributor. Please help.
Hook up a fuel pressure and monitor the pressure if its the fuel pump it will show as a sore thumb when it starts to fluctuates when the pressure drops severely-What you need to do here is when it stalls look for fuel and spark immediately don't make it cool down-Could be the coil when it heats up it breaks down-