Hello, first post. I inherited my father's 1994 3.0 MT 4x4 with 80k miles a couple years ago. Something annoying that happens since I got it is I'll be driving 40-50mph under consistent throttle and it'll bog/hesitate for a second which is quite noticeable. Starts fine, idles fine, runs fine in general...this will happen at least once a drive if not a few times. Most drives are around 25-30miles round trip. I'm not super car knowledgeable, just perform basic maintenance myself so was wondering if there's anything basic I can try or should I just have it diagnosed? Last year I had a stuck valve (exhaust valve on cyl#3) so the heads were cleaned/new guides with new wires, dist cap/rotor, spark plugs, thermostat. That was a $3k job so I really don't want to throw a parts cannon at it. I know new parts can be questionable but this was already happening prior. I haven't been able to find an exactly similar post as most have hesitation upon accelerating or rough idle. Mine is a case of driving fine and then feeling a 'bog'; is monitoring live fuel delivery something most mechanics should be able to do? I just replaced the air filter; old one didn't look terrible.

 

check here or YouTube how to check for how to get codes for ODB1. you might find something to start with.