Loss of power in acceleration from stop to 2000 rpm

1995 Toyota Camry LE 4 cylinder with 292,000
miles. My currently issue is a significant loss of
power during acceleration from a stop. It is usually
the worst getting to the 3000 rpm level. I put my
foot on the gas, sometimes to the floor, and it really
hesitates. Sometimes I have to coax it, pumping the
gas, before it grabs. Once it does, it is totally fine-
drives normally. It's only from a dead stop or going
up hill that I have these issues. About 5 days ago, I
had meineke examine it, and they were pretty
stumped. Because Toyota did not start making
cam's with OBD II until '96, they had to manually
look at the different systems. After about 5 hours on
it, they said they think it's a timing issue- timing belt
jumped a tooth. My dad, who is pretty good with
cars, looked at the timing belt and said the belt
itself looked fine. (He did not completely
disassemble as if to replace it; just took off timing
cover). He said with a timing light he could tell
more, but that is proving to be a difficult tool to
borrow/find nowadays. He also suspects a problem
with the tensioner since it does have a rattling noise
at idle. In a desperate effort to save my beloved car,
(and I love this stupid thing), in the last week the
following has been done: serpentine belt replaced,
ETC sensor replaced, and cleaned throttle body.
Since doing these things, the idle has improved
drastically. When the problems first arose a few
days ago, it had a very rough idle. I suspect
cleaning the throttle body had something to do with
this improvement. A few suggestions from
mechanically inclined friends and online forums
have been thrown such as: checking the EGR valve,
MAF sensor, fuel filter/pump (even though meineke
said it looked fine), clogged fuel injector, or possible
vacuum leak. I am at a loss with what to do next.
Meineke said to junk it and move on (based on
mileage I guess). If this issue is easily and
inexpensively fixable, I want to salvage this vehicle.
It's very reliable otherwise, and I have been
adamant in maintenance. What would be the best
course of action for me to pursue next? Any advice
is welcome and greatly appreciated.