94 Camry
5S FE with AC
168,000 miles (mix of around town and highway)

I am tracking down an issue that is hard to describe, but any of the following might be used: skip, hiccup, lope. I will call it a skip. the issue could also be described as a transmission gear change.

1) the problem seems to occur more when warmed up. especially after highway driving.

2) on the highway, it will occur when the transmission downshifts to climb a hill. about 2 seconds later, there seems to be a second transmission shift. again, this is the feel. it might be described other ways. this uphill climb scenario is consistent.

3) In park, in a parking lot, if I turn on the AC, which adds load, i will get a couple of these skips within a minute of turning on the ac, then it idles OK (idles rough, but characteristic of this engine). if i turn off the ac, i do not get the skips.

but this was only repeatable after highway driving, and I could not repeat after a quick trip around the block. after trip around block, without AC, i had some skips.

4) driving around town, i get these skips periodically. I first thought the transmission was the issue as it seemed to occur with a transmission gear shift.

5) the skips do not occur regularly. at idle for example, it may idle for long periods, and when driving, it may drive for long periods, without problem.

6) when accelerating from a stop, it seems to skip just after pressing on the pedal, somewhat like a hesitation, but more like a transmission gear change. this is not consistent.

RPM speeds (maybe not relevant, but i recorded these when trying to observe the rpm drop due to the skip). approximate - after trip around the block:
idle, park, w/out AC - 750
idle, drive, w/out AC - 750
idle, park with AC - 875
idle, drive with AC - 800
when going from drive to park, the idle dips to 700, then recovers to 750.

A moderate skip seems to drop the RPM by 50 to 75 rpm

Maintenance
Fuel filter? i have no record of a filter replacement (I do not have records before 1999 - will ask seller - my dad). I read online that the fuel filters should not require service on a toyota (?).

spark plugs. replaced 17,000 miles ago.
spark plug wires: i have no record of a replacement (I do not have records before 1999)
distributor: replaced 2.5 years ago. two weeks ago, dealer told me i was getting oil in the distributor due to seal leak

air filter - replaced last year.

Timing belt - two weeks ago, dealer replaced timing belt, other belts, oils seals, water pump. This problem pre-dates this timing belt change.

pulled 3 inch air hose from TB. carmelized, but does not look like anything to worry about. I will try some fuel system cleaner via the fuel tank.

the car seems to get low gas mileage also.

Any ideas you might have would be great.

Any recommendations on what to check, please advise. I have moderate skills, no specialized tools.

Thanks,
Ted

Hesitation under load sounds like an ignition problem. Consider plugs, cap, wires, rotor.

how do you find out if its the wires?

Mileage since they were replaced is one way. With the engine running you could also mist/spray the wires with water in a spray bottle and look for arcing. This is best done in darkness.