i have a 95 4runner with a 3.0. it runs pretty good,but there is one thing that i cant figure out. once it warms up,it gets a miss at around 2500 rpm.the only time i can REALLY hear and feel it is when i put it in park and raise the rpm to 2500-around 3000.it doesnt miss a bit when it is below opp. temp, so i am guessing it could be the 02 sensor.another thing is that i dont have any codes.if it is the 02,could it just be "lazy" or rich/lean biased?has anyone else had this problem?or does anyone have any ideas? all the help i can get is more than welcome!

 

i would start simple, by squirting the plug wires with water while idling, mainly where they push on to the spark plugs, but try at the cap also. if the wires are sealing good on the post or arent cracked it shouldnt arc. most electrical equipment is heat sensitive. so you could have a bad wire that only arcs when they are warm. also pull the dist. cap off and check it and the rotor, and while the cap is off grab the center shaft of the dist. and make sure it doesn't wobble inside the dist. housing. that would throw off the timing and could cause a miss. a bad o2 shouldnt cause a miss, very unlikely anyway.

 

Also, vacuum leaks generally show up after the engine is warm due to the high idle & rich mixture (less obvious then). I had a very similar issue which turned out to be a large hole in one of the A/C VSV hoses. Fixing it made a HUGE difference in response & fuel economy! These engines have a TON of vacuum hoses! The easiest way to isolate a leak is to take an UNLIT propane/MAP gas torch & run along each hose until the idle increases. That is where you start looking very closely; wiggle each hose and listen for the telltale "SSSSSSSSS"...!