{1987 Toyota SR-5 Pickup 5 speed manual 22-RE.} While driving near my house (thankfully) I was accelerating in 3rd gear and heard a muffled pop (or low frequency POOT) near the passenger side floorboard. I turned the truck around and headed back home and noticed while accelerating no gear would register higher than 2200 rpm before I had to (prematurely) shift up to the next gear. So 1st gear gets to 2200 rpm, no more power...shift to 2nd, ok until 2200 rpm, no more power again...shift to 3rd, ok until 2200 rpm and so on. This truck has always seemed to find it's way home and did so that day. Still runs well when idling, seems to have no noticable issues when running while parked. Any ideas what happened?

 

Not sure that this is the answer, but I had something similar happen once.
Ran and idled fine but trying to accelerate, especially above X rpm (don't remember) it fell flat on it's face and had no power and started missing badly.
It was the distributor. Mine is a strictly mechanical advance, no vac advance unit and one of the little C clips holding the internal weights on came off. Result was that the distributor wasn't advancing as it should as RPM's increased.

For you this could mean that either the mechanical advance, the vacuum advance, or both aren't functioning properly.
To diagnose you could put a timing light on it (with the vac still hooked up) and start throttling it up while watching the mark. Should advance pretty linearly with RPM's. I believe it hits max advance somewhere around 3000 rpm and it's about 34° max advance (delay timing light is handy for checking this).

Hopefully this helps!!
Good luck and let us know what you find.

 

Thank you for your reply! I will check it out...

 

Does it have the original plastic timing chain guides?

My guides had broken, and somehow the chain slopped around enough to skip some teeth advancing the timing of the cam causing no high rpm power.

If your guides are still good, this DIDN'T happen.


A quick test is to see if your distributor timing has gotten really really advanced. (distributor is driven off cam)

 

Well...I found out what the problem(s) was/were: A severely rusted gas tank..which led to Fuel Pump having issues. That and the loss of the tip and ceramic of spark plug #3 created a loss of power situation. Fortunately, I was able to keep the truck running (for 15 min every week or 2 weeks in winter) for 5 years while waiting to find the $ and my local miracle worker (highly skilled mechanic) was able to replace the gas tank, fuel pump, sending unit, fuel lines, fuel filter and put 4 new plugs, cap, rotor, etc in January. He checked the timing and she purrs like a kitten now. Thank you again for the suggestions and I hope this information helps someone else with a similar problem.