Right after the timing belt was replaced on a '95 Camry, the power band of the engine changed drastically. I think it was installed retarded. Low end power up to 3000 rpm's is about half of what it was prior, but stronger 4,500 on up. The idle is a bit rougher. No check engine light is present. MPG suddenly dropped from 25 to 19 with the new belt. The acceleration is especially poor when the engine is cold. I would guess 0-30 in 7 seconds, with 0-10 probably taking almost 4 seconds. The engine runs very smoothly from about 3,500 on up. The car ran perfectly fine before the belt was changed, and had a fairly flat power band. The mechanic is sure the belt was installed with correct phasing. The mechanic is claiming that some totally unrelated problem caused the drastic change such as the timing. It acts somewhat similar to a muscle car with a drag race cam - no bottom end, then suddenly comes into the power band. It has about a 50 rpm surge at low rpm load, but none above 3,000 rpms under the same load.
What exactly does the mechanic say it is? How much does he say it will cost
to fix? Does he agree with you that it was running good prior to the belt
As a general rule of troubleshooting you look for the thing that changed right before the problem. So it sounds like you are looking it the right direction. It does sound like a timing issue. If the timing belt was installed properly somethings else may have gotten bumped.