I just recently had my 1994 Toyota Camry 2.2L engine rebuilt, which has an Automatic Transmission. It has 189,000 miles on it, which is low for a Toyota engine to require a rebuild. After having it rebuilt, I took it for a test drive.

From a stop to approximately 30 MPH the RPM indicates 3500. I've seen it go as high as 4000 once. It is obvious that it is not shifting at the correct time and at the time of posting I have105 miles on the rebuilt engine. I'm not jamming on the gas pedal - I'm giving it a normal and smooth acceleration. It was not doing this before I had the engine rebuilt and it makes me wonder if the rebuilt engine is magnifying problems that existed before with other components. I took it back to the shop and asked for advice, and they mentioned that they don't touch anything related to the transmission. They also said that the Throttle Position senson could be failing.

Does this sound like a resonable cause? Any other ideas?