Regal won't accelerate, get code P0131

Hi, I have a 2000 Buick Regal LS with 71K. Lately the car has been unresponsive when accelerating. I will stand on the pedal and the RPMs will slowly increase, but the car simply stays at the same speed. This is not always the case, I consider this problem to be intermittant, but lately its been more frequent. Once a month my check engine light comes on, I pull the code (P0131, H02S low voltage for oxygen sensor) and clear the code. I've recently replaced the oxygen sensor and all 6 plugs. fuel pressure seems normal, and TPS resistance responds properly when I pull on the accelerator cable. I checked resistances across all three coils and they all read as they should.

Other symptoms...sometimes I'll be at 70 mph with Cruise Control on, and when I come to an incline, the car struggles to maintain speed...dropping to 60ish before downshifting and RPMs jump to 4500 to increase speed.

Please help!!! Could this be a MAP sensor issue? I intend to try switching this with the one on my wife's car (she has Impala with 3800 engine, so most parts should be interchangeable).

Thanks,

Nathan

is the catalytic conveter plugged?

What is the best way to check the catalitic converter?? Can I do it myself?

you can do it with a vacuum gauge hooked to an intake port or remove the 02 sensor ahead of the conveter and using an adaptor check for positive pressure in the exhaust.

New Development:
Taking the advice of a friend, I tried unplugging my MAP sensor and then driving...and the problem of non-acceleration and missing went away! So, I spent $60 on a new sensor, and replaced the old one. However this did not solve the problem. It still exists, except when I drive with the MAP sensor not hooked up, then it accelerates just fine.

Is this a faulty wire? an ECU problem?? Anyone know further testing I can do to isolate/identify the problem?

Thanks,

Nathan

When you unplug the MAP sensor the computer uses the base fuel map program.Which will be richer than adaptive. This is to help protect the eng from damage. What Jeff said; also have you checked for vacuum leaks.Low fuel pressure or possible injector problem.

Of course it has more power, it's pig rich with the map disconnectted!

I do not hear any type of vacuum leak, is there a different way to diagnose this, other than audibly?

Thanks,

Nathan

yes listening is the least effective! google it and i think there is an article on this site somewhere. any haynes or chilton manual should have it explained in the first couple of chapters