i have a v6 3.0 4runner 1990, i recently replaced both head gaskets, the thing starts and runs. but wont rev above 3 or 4 thousand rpm,, i set the timing, when i checked for problem codes the engine light just flashes constantly with no intermission, no code,, i reset the efi fuse,, made no difference, the only thing that seems to work is if i take the neg. terminal off the battery and let it sit all night , in the morning i hook it back together and it will rev to redline.. makes no sense,,then after a little bit the problem comes back. when you rev it up its like its retarding the ignition or like a rev limiter on a motorcycle or cutting the fuel. like its in a limp mode so you cant damage the engine.. the check engine light has never come on either.. has anyone experianced this,, any help would be great,, thanks

 

is it a sharp bounce of a 4 or 4 rpm?

 

when first reading your title, fuel filter came to mind, and even more so when you said it works fine in the morning then begins to drop off. have you checked your vacuum advance on the dist? could be a problem there...

 

I second the fuel filter, could also be a plugged Cat

 

so its been a couple days, but i figured it out, it seems the smaller ground wire that goes from the negative battery terminal to the engine fire wall was broke internally. after i fixed that it will redline every time. it doesnt have a cat. and i got a new fuel filter with it when i bought it,, so im going to replace that just to be safe. thanks for the advise guys,,, cheers

 

Howd the runner do in the snow?

 

unfortunatly,, not well,, the fourwheel drive is not working,,im working on that now, ive got no 4wd light, but when i drive forward in 4wd i can see the front driveline turning but the front end is not engaged in 4wd,, so ive got to troubleshoot the problem, wheither it is a vacumm issue or bad connection at something, not sure,, lucky for me there are alot of threads on this problem with the automatics, so threw trial and error ill figure it out,, my clymer manual has nothing on this issue and im to stubborn to take it to a stealership. i personally dont like the snow, i would rather go to it, instead of it coming to me, oh well,,,, atleast it comes in inches and not in feet.