Similiar Issue Fixed, mostly
I just brought a '95 4Runner V6 with 144,000 miles. Today I drove her on a moderately hilly highway for around 30 miles. The truck seems to be lacking in power big time. I can hear the valves knocking harshly whenever I put my foot down & on one long hill she dropped to an embarrassing 40 mph & then proceeded to blow the pressure cap on the radiator. Had to pull over for an hour to let her cool down & add about half a gallon of water.
So basically the engine is a dog & overheats. The previous owner installed a new timing belt & water pump, presumably to help address these two issues. Any ideas what I should do other than return the vehicle?
I have a 94 V6 with 264,446 mi (still running) quick back story of issue:
usually the engine would chug and down shift or shift improperly going up hills more than usual causing a low speed, however no issues on flat highway except the shifting into overdrive because of the temp sensor being located near coolant hoses and blah blah,
Recently it started to shudder violently during acceleration at anytime hill or flat land, looked into the issue turning out to be loose sparkplug wires and faulty distributor cap, soo replaced sparkplugs, wire and cap as well as rotor, which fixed the shuddering issue.
BUT as soon as that was fixed started to lose all power during acceleration and would chug even from a start, shifting was terrible, took it to a trans specialist who said it was not the trans but an engine performance problem, looking into it more and turns out it was a BAD CATALYTIC CONVERTER, that was clogged and not letting the exhaust out, runs like a charm the power is back still has a slight loss of high end acceleration at 65mph and above but power is back and shifting is back to normal. i might still have
I would check your exhaust system as well as your air intake a lack of flow either to the engine or from it can cause loss of responsiveness and poor acceleration especially up hills good luck, assuming you haven't already solved your issue b/c this is an old thread