My son's girlfriend has a 2000 Intrepid with a 2.7 V6.
It started acting up on her, so I offered to swap cars so that I could take a look at it.
The car starts and idles fine, but starts bucking and surging under light acceleration in the 1500 - 2300 rpm range. Flooring it seems to smarten it up, so that tells me that it's not a fuel delivery problem.
This behaviour is the same in all gears., even at highway speeds.
When I got it back home to my garage, I tried to feather the throttle up into that RPM range with no load on it, but found it virtually impossible to maintain a steady engine speed. No obvious misses, no backfires in either the intake or exhaust.
I "cured" my 2004 Pontiac GP with a can of each throttle body cleaner and MAF sensor cleaner ... so I had a can of each on hand.
I discovered that this car is not equipped with a MAF, so I cleaned the throttle body and the TPS (externally) and blew it dry.
I then took it for another road test, and found no improvement.
There is no "check engine light" on, and no stored codes either (as long as I am using my new Equus 3100 code reader properly)
The code-reader would not return the vehicle information (i.e. VIN) and the "C" is flashing, indicating that it was unable to succesfully run a test on the catalyst.
I'm certainly not a diagnostic expert ... but I have a hunch that it's the TPS that's at fault here.
I'm sure not liking what I have been reading in regards to 2.7's in general. LOTS of customer complaints ... but then again ... does anyone ever use the internet to tell others about their positive expereriences?