Engine runs rough-need ideas

I'm looking for some ideas. I have a 95 Cirrus, 2.5L V-6, 180,000 Miles. I have been experiencing problems accelerating from a start (especially when the engine is cold). It dies out and stumbles very bad with an occasional backfire. If I feather the throttle up to about 5 MPH it runs fine. The other symptom is that when cruising at about 70 MPH, it will occasionally stumble (almost like it is starving for gas) then run fine. Twice now, it would not start. A day later it starts fine. So far I have replaced both O2 sensors, idle air bypass motor, MAP sensor, plugs and wires, EGR valve and timing belt. The problem has greatly improved with these changes, but still exist and seems to be getting worse. Fuel pressure is 47 PSI and stable (checked in garage not while driving). Three things I can think of are fuel pump, Coil, or Cam position sensor. I can't scan the car because it is a transition year and is not supported by most hand held scanners. Any ideas?

180,000 miles your engine might just be dieing. Have you checked compression? What about the TPS (throttle position sensor)

I would also suspect the throttle position sensor. Get an analog multimeter. Not a digital because they don't respond fast enough. Disconnect the TPS from the harness, set the meter to read resistance, connect the meter to the TPS and slowly sweep the throttle and watch the meter needle for jerking.

If you want to do a quick check, you can do this next one as well. I now this works on a Ford, but I've never tried it on a Dodge. With the engine running, tap on the TPS very gently with a metalic object. Listen to the injectors, not the engine. If the TPS is bad, you'll hear the timing of the injectors change.

Russ

Originally Posted by rkfsm

If you want to do a quick check, you can do this next one as well. I now this works on a Ford, but I've never tried it on a Dodge. With the engine running, tap on the TPS very gently with a metalic object. Listen to the injectors, not the engine. If the TPS is bad, you'll hear the timing of the injectors change.

Russ

Cool idea never thought of that. I would also check for a plugged injector too. I've had to replace 2 on a neon already.

One other thing too...... On some of the Dodges, particularly the newer ones, the TPS has to be calibrated after installation. Don't know how to do it, but my maint manual says it needs to be done.

Russ

Check the EGR valve, common problem on the 6g73.
Also check the O2 sensors.