1999 VW Passat is slowing down even whn I press the gas.

vacuum leak check the hoses.

be checking emissions controls for vacuum leaks especially with the brakes..

That indeed is strange. It could be one of or a combination of things a number of things: a dying fuel pump, bad plugs or plug wires, a dirty fuel filter which needs replaced, carb problems, water in the gas. If you have really high mileage on the car, it could even be a bad clutch getting worse. Other than those admitted "guesses" I have no idea. If this has never happened before, I would give it a new fuel filter, put in a good additive like Sea Foam, make sure it is firing on all cylinders and take it from there. Good luck, bro . . .

This could be any number of things. I would guess there is a check engine light on, you would need to have that checked, they will do it for free at most auto parts stores. A local VW dealer or mechanic would be best to check with though.

Symptoms- Engine Light ON (or Service Engine Soon Warning Light)
- Lack/Loss of Power
- The engine may be harder to start
- The engine may stumble or stallPossible causes- Ignition/Distributor engine speed sensor harness circuit is open or shorted
- Ignition/Distributor engine speed sensor poor electrical connection
- Faulty Ignition/Distributor engine speed sensor
- Faulty Crankshaft Position sensor
- Low battery charge
- Faulty Engine Control Module (ECM)When is the code detected?The P0322 code is triggered when the Engine Control Module (ECM) detects no signal.P0322 VOLKSWAGEN DescriptionIgnition failure sensor is used to check whether the spark ignition is occurred correctly or not and also used to tachometer drive. The sensor monitors the voltage difference between a resistance which is on the battery circuit for ignition coil. When the ignition coil works properly, the electric current through the resistance is detected as voltage drop. This is confirmed for every ignition event with the crankshaft sensor and the camshaft sensor. If ECM detects a malfunction, no ignition is possible, so the engine would not start. If there is no ignition signal for a predetermined cycle for one or two ignition coils, an ignition coil circuit failure exists.

2001 elantra gets 300 miles per tank of gas regular unleaded
slow to respond when accelerated 105 K original miles recently purchased
no check engine lights most parts look original engine revs up but tranny seems slow to respond?

You have a bad coil pack, they usually crack from age and heat. It's best to replace them all. Check for a VW recall on this item.

hallo
remove, clean trottle body. use trottle body cleaner(spray) or nitro and some small brush)It should shine from inside, allso/especialy below the flap (hatch). if you have possibiliti do basic setting (tester).
it is not ECU faulty
marko

p1545 is a throttle control malfuction code

You can try to reset the throttle body by opening the hood and drivers door then turning your key to the accessory position. You will hear the throttle body whir and click. It may take up to two minutes. Afterward, the car will relearn your habit of driving and adjust accordingly.

I researched this & you need to replace the throttle body gasket & get the throttle body re-calibrated. Seems to be dealer only. Also, the t.p.s. (throttle position sensor) could be bad.