My 2002 buick lesabre stalls when I step on the gas. It idles just fine. I put a fuel injector tester on it, and it read 42 PSI with the key on. I started the motor and it read 42 - 43 PSI at idle. I pushed on the gas and it increased to about 50 PSI, but began to stall out, very badly. After stopping, it hold the pressure pretty good. Any suggestions?, and What should the pressures read?

Hey robert, sounds like the a/c compressor may be locked up...you can get a new compressor or get a "bypass kit" that replaces the compressor with a pulley and it should be fine..

Some parts houses will assist you in getting a short serpentine belt that will allow you to eliminate the compressor with just a shorter belt..(IF the configuration wil allow)..

I have ran into problems like this, so I replaced the ECM and that fixed the problem, you can try this, may help.

ck if you have adequate fuel pressure 30-40 psi. if not it may need a fuel pump and filter replaced.

Fuel injectors go bad on these engines, you can find re manned ones for 30 bucks. If you have an engine light on get that read. Change your coil/wires/plugs also. Is the lower intake manifold gasket leaking coolant yet? You may want to get that replaced also. Check the TPS too (throttle positioning sensor) those will also cause your engine to act up

DO A SPARK TEST USING A SPARK TESTER AND USE A FUEL PRESSURE TESTER GAUGE TO DO A FUEL PRESSURE TEST.FUEL PRESSURE SHOULD BE 41 TO 47 PSI.IF YOU GETTING NO SPARK.CHECK THE IGNITION MODULE FUSE.IF FUSE IS GOOD.SCAN IT TO CHECK FOR IGNITION MODULE FAULT CODE.PCM FAULT CODE CRANKSHAFT SENSOR + CAMSHAFT SENSOR CODE.IF YOUR FUEL PRESSURE IS 0 CHECK FUEL PUMP AND FUEL INJECTOR FUSES AND RELAY.IF OKAY FUEL PUMP FAULTY.BY USING A SCANNER IT WILL SAVE YOU TIME AND MONEY.NEW FUEL PUMP ABOUT $300.00 AND A NEW IGNITION MODULE ABOUT $200.00.

sounds like the egr valve is sticking. remove and clean. or a vacuum hose is leaking

The fuel pump may be about done. Check fuel pressure at the test port in the fuel rail over the injectors (rent the pressure tester)--it should be in the 40 to 50 PSI range with engine idling. If the pump continues to run with the key on, but the engine off, shows that the pump is about worn out. Hope this helps!

Sounds like the plugs are not firing hot enough on initial start-up. Try a quick spark plug change, and clean throttle body. The gas being injected, isn't being burned fast enough by the plugs, which causes the car to have a hard start-up. You may try a higher octane gas or Lucas injector cleaner with your usual octane rating. Lucas comes in a very small bottle, and works very well in my opinion.

Question:
Explain Triggering!

Fuel injectors do either one of three things:
1) Clogged - fail to pass gas through them when a voltage triggers them to fire/spay gas.
2) Electrical connection breaks inside the injector - 'throw it away and get a new one'
3) Signal being sent to the injector isn't being sent.
Swap a good known working injector with the suspected bad one. See if there is a change!
NOTE: Many times when the car is on and standing still idling, removing (a or 1) of the fuel Injector's electrical connection from it interrupts how smooth the engine idles.
If no idle interuption - injector isn't working at all
if a slight idle interuption - injector is working fine
if a major idle interuption - possilbe there are other injector's that aren't working either.
Blessings,
A/V Media Guy

Check fuel pressure.