Hey guys, I've been searching around without much luck. Lately, at higher speeds my 4runner has been surging and bucking. Idles just fine, around town runs great, but when I take it on the highway it almost feels like its missing. Searched around for what could be causing it (came up with lots of fuel related answers like injectors, gas tank, etc.), just checked for codes and I believe I'm getting a #2 - air flow meter signal and a #8 - intake air temperature signal. I figure the AFM signal might have something to do with it, so I'm going to do some testing with that. What exactly is the #8 code telling me? Any other ideas on why it would surge like this?

Thanks in advance

 

A friend of mine has a spare AFM so I'm going to try and throw it on tonight and see what happens.

Any other ideas? Could it be the fuel filter?

 

Got rid of the codes, also put in a new air filter. Still surging when I give it gas when rpms are above about 2500 - 3000. What do you guys think? Fuel filter? Injectors?

 

Thanks for the input, I'll check into that. I hope its that simple.

 

Did you ever find out what the problem was? Mine is doing the same thing except at any speed. When I accelerate it surges a lot, if I maintain the speed it is smooth and idles smooth too. Vacuum lines look good and the tune up was only about a year ago. (87 runner)

 

Just had a look at the vacuum lines and they are all routed to the right places. Just kinda going through all the possible problems one by one, not a lot of time to work on it right now during school but it still drives fine as long as I granny it. I'll get her figured out pretty soon hopefully. Still open to suggestions...

 

I think I read something about a clogged EGR valve or something causing surging and bucking? Don't know if that makes sense, maybe this will spark some ideas from others

 

Changed plugs wires cap and rotor and its running strong.

 

good to hear!