I haven't been able to find anything similar yet, but was hoping someone had some advice or recommendations...

Yesterday I noticed that my 4runner acts strange at high rpms (~4500) when trying to shift. I was accelerating out of a rest-stop to get in front of a semi-truck, at the 1-2 and 2-3 up-shifts, it felt like either the engine was cutting out or maybe the tranny was slipping. The truck just kinda shuddered and felt like it was having trouble locking up, letting off the gas let it shift and the problem went away. It has been driving fine before then, and was fine after; I was able to recreate problem under hard acceleration again. I was in the middle of a 3 hour trip, no other problems noticed.

I'm hoping it is something else like TPS or something that is just acting up, but I have no idea where to start, the TPS was just something else mentioned on another site, with another vehicle with sorta similar problem

btw, auto transmission, stock gears, not supercharged, not sure what else relevant

 

Maybe you can hit your local autoparts store and have them do a scan and see if it threw out any codes. I had a similar problem and it took some time before a check engine light finally came on - then I found out it was a spark plug issue. Just one possible way to start your diagnosis.

 

tranny--need more details, last time it was flushed and with what? how many miles on tranny? etc etc

tune ups, when is the last time and etc.. sorry for the questions

 

yeah, thats what has me a little worried... about 5,000 or so miles ago the tranny cooler sprung a leak in the radiator, it was caught within a day, towed, and I installed a new radiator (and aux cooler too). The entire system was flushed with about 30 quarts of tranny fluid (same stuff any shop would use, but nothing fancy) and has been clean since then.

It currently has ~100,000 miles on it, was drained/refilled ~85k, was flushed refilled ~65k, before that I do not know

as far as general tune-ups, I did plugs/wires about 15-20k ago, I keep the MAF and TB clean as possible (haven't checked in about a year), everything seems to be running fine except for this...

 

two tran shops and a dealer service manager have all said it doesn't sound like tranny, more like engine misfire. So I will try and get codes pulled tonight after work. In the meantime, any other ideas?