Hello everyone this goes out to all my technicians. I have a 2001 Ford focus that has been in the family for a while. It has a fully built 2.0l zetec and it is turbocharged with a custom tune. My car was running perfectly and about a week ago it decided to stop running. I was driving on the highway came under boost and everything seemed to be ok. I exited the highway and my car died at the stoplight. So i figured no big deal probably a vacuum line that blew off or something. Well i have been working on the car for a few days now and this is what i have done so far. First would like to explain what the car is doing. When you start the car it will spike to 3500 - 4000 RPM and die. So first i verified all the vacuum lines and ensure that none of the lines are broken. I have capped the lines to see if improves conditions but continued to do the same thing. During further inspection I realized that my timing belt was extremely loose. So i replaced the timing belt thinking maybe it jumped timing. Condition stayed the same. So then i verified fuel pressure and checks out at 40psi. Verified the timing of the motor. The only thing that looked abnormal was the IAC so i replaced the IAC and the condition stayed the same. I have also replaced the MAF sensor and the fuel filter and spark plugs. I know not very good troubleshooting but at this point im at a loss. If anyone can help it would be greatly appreciated!!