Hello: Timing on my 1998 V6 Tacoma is extremely retarded....so much so the mark doesnt even hit the timing tab. It does advance when rpm increased. It backfires on descents and has absolutely no power to climb a hill. There is no check engine light illuminated. There were no trouble codes with OBD2. I have replaced plugs, wires, fuel filter, and checked the coil overs with an ohm meter. Everything seems fine. It has 93k on it so I know it is due for a timing belt. It has been suggested that the belt may have jumped a tooth....but I didn't want to dive into that until I have tried other possibilites. If it jumped a tooth would it most likely advance or retard? Does anyone have any other suggestions or seen this before? Thank you very much for your input.

 

The best thing to do is to hook up a Scan Tool with monitoring software (laptop) and get the actual timing reading, then compare to the FSM spec range. The spec range should be 8 - 12 degrees BTDC @ idle. I am not certain, but I believe various temperature parameters can influence timing, such as IAT, coolant temp, etc. I guess it's possible that one of those sensors is messed up, but you would have to confirm that with a Scan Tool as well.

Once all that is exhausted, I would go for the timing belt. As you mentioned, it needs it anyway.