All,
My 99 with a little over 200K has started to exhibit intermittent overheating and has been occasionally dropping RPMS. The RPMs will drop when idling or even accelerating at around 40MPH. The 4runner will also overheat when pushing RPMs above 3500 while going 70+ MPH over a mountain pass. Usually the overheating will occur after running hard and not necessary while heading up the pass. It also doesn't overheat every time I push the RPMs.
The check engine light would come on indicating a cyl 3 misfire or random misfire when really pushing it up a mountain pass, but again not every time. I've just changed the spark plugs and wires, which helped but didn't completely fix the problem.
I've taken it to the dealership twice. They preformed a leaked down test which showed my head gasket isn't busted, flushed the coolant, and replaced the thermostat. They said the injectors checked out but they could still be the problem (say if they were running at 80% and only fail when really pushing it).
After a road trip of nearly 3000 miles over 12 days I again overheated three times (never all the way to red) and saw the check engine light 3 times (blinked but didn't stay on). Each overheat was in temperatures over 80+ degrees heading up hill on the highway and the check engine light showed up only when pushing the RPMs. The overheating and the check engine light did not always coincide. For the last 900 miles I kept the RPMs below 3000 and didn't have an issue. With premium gas I was able to get 20-22 MPG. It also seems the loss of RPMs is not as frequent/not existent with higher octane fuel.
The 4runner runs great when taking it easy and maybe that's just what I need to do from here on out. The overheating could be caused by a spring from a faulty radiator cap falling into the radiator a few months ago, but aside from trying to stick a magnate down there I don't know how to get it out. Any thoughts or similar experiences will be helpful.
Thanks
My 99 with a little over 200K has started to exhibit intermittent overheating and has been occasionally dropping RPMS. The RPMs will drop when idling or even accelerating at around 40MPH. The 4runner will also overheat when pushing RPMs above 3500 while going 70+ MPH over a mountain pass. Usually the overheating will occur after running hard and not necessary while heading up the pass. It also doesn't overheat every time I push the RPMs.
The check engine light would come on indicating a cyl 3 misfire or random misfire when really pushing it up a mountain pass, but again not every time. I've just changed the spark plugs and wires, which helped but didn't completely fix the problem.
I've taken it to the dealership twice. They preformed a leaked down test which showed my head gasket isn't busted, flushed the coolant, and replaced the thermostat. They said the injectors checked out but they could still be the problem (say if they were running at 80% and only fail when really pushing it).
After a road trip of nearly 3000 miles over 12 days I again overheated three times (never all the way to red) and saw the check engine light 3 times (blinked but didn't stay on). Each overheat was in temperatures over 80+ degrees heading up hill on the highway and the check engine light showed up only when pushing the RPMs. The overheating and the check engine light did not always coincide. For the last 900 miles I kept the RPMs below 3000 and didn't have an issue. With premium gas I was able to get 20-22 MPG. It also seems the loss of RPMs is not as frequent/not existent with higher octane fuel.
The 4runner runs great when taking it easy and maybe that's just what I need to do from here on out. The overheating could be caused by a spring from a faulty radiator cap falling into the radiator a few months ago, but aside from trying to stick a magnate down there I don't know how to get it out. Any thoughts or similar experiences will be helpful.
Thanks
