1994 Passport engine miss

I have a 19994 with a 3.2 V6. Engine has a miss in lower gears mostly in first and second. When I get her up on the highway she runs great. I had a mechanic recently tell me he suspected it was a valve but I thought if it were a valve it would be consistent all the time. Any insight would be appreciated.

When was tha last time you replaced the fuel filter?

ever had the injectors cleaned?

I haven't done anything as of yet to it. I am not sure of the history as I bought it at an auction.

Pop the hood in the dark with engine running and see if there is any arcing from the spark plug wires.

I had a miss on my 95 rodeo, it was constant... Turned out to be an injector. You may want to do a compression check. Or, do the poor mans compression test. Remove the spark plug wires from the coil and turn the engine over, if you hear a wah, wah, wah, wah, wha, wha, constant noise from the starter you probably have good compression. If you hear wah, wah, wuh, wah, wah, wah, wah, wah, wuh, you may have a bad valve.....

Also seems to lose power at times. I do have a slight tick in the lower gears. I have been doing some research and everything seems to be pointing to the timing belt tensioner which is infamous apparently. I have 106k on the engine so it may be due.