ok so here the deal. I think this started noticing this about a month ago. basically I have no power up hills. I mostly have noticed this in the morning on my way to work. as soon as I get on the high way my 90 4runner wont accelerate. Ill have the gas pushed half way down and the tac will sit at 2500 rpms and im going about 35 mph, if I push it further it will rev to 3000rpm but instead of going faster it slow down, eventually after driving long enough it drives normally. I also noticed this is more of a problem when its cold or the engine is cold. what could be causing this? btw I recently had to replace the cat because it was stolen of my truck but i dont remember if this happened before or after i started having this problem

 

is your 4runner stock or lifted and if lifted what size tires

 

every thing is stock

 

i have the same problem but mines an '86 pickup and its carb'd...as long as my motor is warm it runs fine..but if its cold..i have no power..lol..

 

to the op, unbolt the flange on the front of the catalytic converter. just enough to cause a fat exhaust leak. it will sound like garbage, but see if it runs better.

you may have a plugged cat.

that is what happened to mine, it started losing power gradually till i got it figured out

 

well when the original was stolen they cut it out. so the new one was welded in

 

bummer

 

When was the last time you replaced the fuel filter ?, that can and will cause a loss of power if its plugged.

 

i have had it for a year and a half and have never changed it.

 

after a reread it definately sounds like you fuel filter

 

well im going to take it in tomorrow, now that its getting cold up here in the twin cities its gotten even worse. nd on top of that there is a poping niose that goes along with it.

 

took it back to midas to check the cat. they said that was fine. the thought it might be the fuel dampener or the timing. when they did the tests they found nothing. took it home and today after work it died on me twice and then the battery was dead also. i have a new battery and alternator. so i have no idea whats going on.

 

how hard is it to replace the fuel filter? would doing one of those fuel system clean outs the sell and the oil and lube places help?

 

vacuum line!
check those. i forgot to hook one up after tinkering under the hood drove me up a frigin wall till i saw it unplugged. hooked up reset computer PERFECT!