Welcome to Allpar. Listen closely for a hiss. A spray bottle of water is good for detecting vacuum leaks.
A rubber donut seal can easily fall off the EGR tube when putting it back together.

 

. . . .I have a 2003 pt cruiser turbo. Upgraded turbo, cold air intake. I just replaced the fuel line to the injectors, the thermostat, and i had disassembled the intake manifold. After putting everything back together I'm getting a real high idle starts at 1800 then goes to between 3000 and 5000, once i put it in gear without releasing the clutch then it lowers to about 2000rpm. . . . .

The high idel is caused by a vacuum leak in the intake system downstream of the throttle body. A vacuum leak causes extra air flow introduced into the engine beyond what is expected at the throttle body. To keep the air - fuel mixture chemically balanced ( stoichiometric ) the PCM / powertrain control module adds more fuel. Add more fuel and air and it is the same as opening the throttle more and the engine speed increases.

. . . . I do know the gasket for the upper intake manifold tore a corner off. Would that cause the high idle? Currently i have no check engine light. . . . .

If it is a paper gasket any tear or even a sharp crease in the gasketing material can cause an air leak even when sandwiched in place between the adjacent, sealing surfaces.

Fastest way to determine the leak area is to use a smoke machine and inject smoke into the intake system. An automotive repair shop can perform a smoke test but you will probably pay about $100 for that service.

You can build your own smoke machine for less if you want to go that route. Attached video link shows one way to build a machine.

If you do not want to use a smoke machine do the "brute force" method lmentioned by ImperialCrown. Spray water around suspected leak points and see if engine idle speed changes.

Attached is a schematic diagram of the vacuum line connections on a turbocharged engine. Very busy but check all your connections.

 

The high idel is caused by a vacuum leak in the intake system downstream of the throttle body. A vacuum leak causes extra air flow introduced into the engine beyond what is expected at the throttle body. To keep the air - fuel mixture chemically balanced ( stoichiometric ) the PCM / powertrain control module adds more fuel. Add more fuel and air and it is the same as opening the throttle more and the engine speed increases.



If it is a paper gasket any tear or even a sharp crease in the gasketing material can cause an air leak even when sandwiched in place between the adjacent, sealing surfaces.

View attachment 97614

Fastest way to determine the leak area is to use a smoke machine and inject smoke into the intake system. An automotive repair shop can perform a smoke test but you will probably pay about $100 for that service.

You can build your own smoke machine for less if you want to go that route. Attached video link shows one way to build a machine.

If you do not want to use a smoke machine do the "brute force" method lmentioned by ImperialCrown. Spray water around suspected leak points and see if engine idle speed changes.

Attached is a schematic diagram of the vacuum line connections on a turbocharged engine. Very busy but check all your connections.

View attachment 97615

Thank you i found the vacuum leak and fixed the high Rev. But now I'm having a misfire. I've replaced spark plugs, wires, fuel injectors, and I've tried 3 different brand coils but every one made the car run very poorly in a different way and undrivable. I don't want to have to replace the ecu because it's expensive. Is that most likely where the issue is?

 

 

Which cylinder is misfiring or is it sporadic?
Any fault codes?

 

Where was the vacuum leak at