The easiest way to find a vacuum leak involves using any brand/type of carburetor cleaner or any some other type of cleaner in a spray can or spray bottle. With the engine running you spray around the suspected area . If there is a leak at the location you are spraying the carb cleaner, you will immediately notice an increase in the RPM of the engine. You can use this method to find cracks in a vacuum hose that are very hard to see if they are surrounded by wiring harness' and other items. This also works if you have a carb or throttle body base gasket leaking, intake manifold gasket leaking or even mismatched manifold with the cylinder heads.
Check for vacuum leaks.
Vacuum leaks. Get a can of throttle body cleaner and with the engine idling and warm, spray the throttle body cleaner anywhere you have or see vacuum lines. Just a small squirt and see if the engine picks up revs. If it does, you have a vacuum leak. Fix that oen and then go spray again at others. While you are there it's best to try to locate all. The engine idles fine because the engine is not under load and your ratio of fuel to air will let the engine idle but when you press the throttle that puts the engine under load and now the engine suffers from too much air due to the vacuum leaks and it stumbles.
Check for vacuum leaks before you go any further. If you hear a hissing noise, that's probably a vacuum leak. You can use a smoke machine (with the engine off) to pump smoke through a vacuum hose into the intake to help locate hard to find leaks.
check your timing and vacuum advance and vacuum leaks. from there check fuel delivery system.
To check the purge flow on a 2004 PT Cruiser, first locate the purge solenoid, which is typically found near the engine or on the intake manifold. With the engine running, disconnect the purge line from the solenoid and use a vacuum gauge to measure the vacuum pressure while the engine is at idle. If there's no or insufficient vacuum, the solenoid may be malfunctioning. Additionally, you can check for any leaks in the vacuum lines or inspect the solenoid for proper operation.
Power loss on an engine is generally due to an air problem. Check the vacuum lines on the engine to see if there are any leaks. Leaks in a vacuum line cause a car to either run to lean or rich. This will negatively effect the performance of the car.
Check for vacuum leaks.
To change the vacuum hose on a 2001 Hyundai XG300, first ensure the engine is off and cool. Locate the vacuum hose that needs replacing, typically found near the intake manifold or vacuum source. Disconnect the old hose by gently pulling it off the fittings, then attach the new hose securely to the same fittings. Finally, check for any leaks by starting the engine and inspecting the connections.
You probably have a vacuum leak and aren't getting vacuum to the actuators. With the engine running, listen for vacuum leaks under the dash. If you don't have any leaks there, check under the hood to make sure the vacuum line THERE isn't disconnected.
Check for vacuum leaks and good electrical connection at the EVAP vent solenoid
First, check the EGR valve for leaks and/or proper installation. If that's not it, check for vacuum leaks.
Could be vacuum leaks. The year and engine info would help us help you.