I've been having an annoying issue with my 2002 Camry with 150k miles. When accelerating from a stop the car will surge and then slow down but the tach will stay steady. Seems to be getting worse now after replacing the MAF sensor. Originally the car had the check engine light on so I scanned the codes and found P0420, P0440, P0441, and P0446. I replaced the Air / Fuel O2 sensor and the Mass Air Flow sensor and cleared the codes. Drove the car over 600 miles with no check engine light but it is now surging when accelerating from low speeds. Engine sounds like it's racing a bit but then slows down. Car lurches a bit and then slows down even though I have constant pressure on the gas pedal. I know I have to change out the charcoal canister ($250) but it is so cold now I don't have the strength to crawl under the car. What's odd about this problem is the check engine light has been on for a long time and the car ran just fine with no change in driveability but recently it is getting difficult to drive and after filling up the gas tank it is difficult to start the car. Could a bad switching valve at the charcoal canister cause such issues or do I need to change out the entire unit? One other note: when I went to get the car inspected it would not pass since the computer was giving off the "Not ready" status "Error in evap system".

 

Automatic trans? Tach RPM stays steady but car speed does not?

 

Automatic. Engine sounds like it is speeding up but the tach does not change very much. The car speeds up but then slows down like it isn't getting enough gas. As soon as I let up on the gas pedal the engine noise goes away. It almost reminds me of when the gas line freezes up and the engine is gas starved. It's been below freezing these last few weeks which might be slowing the fuel movement but I can't imagine it would do it all day long.

 

The engine RPM remains constant but the car MPH is changing.

Try to determine if the issue could be a failing trans or torque converter. Or something wrong with the differential. Try shifting to Low manually. Turning off O/D.

Check transmission fluid for condition (color) and level. The more red in color the better, the blacker the worse.