442man

I have an 87 4 runner with a 22RE. Runs great, all new plugs, wires, etc. The engine seems to miss when I am not accelating. The problem goes away immediately when I accelarate. It has 235,000 miles and the problem just recently started. I have oversize tires and wheels but don't think that has anything to do with the problem.
The mechanic says all the plugs and wires are good. I have not tried a Toyota dealership yet but am lost as to what the problem could be. Could this be a timing or electronics issue?
Thanks for the assistance.
Regards,
442Man

abecedarian

by nature, the engines do idle a tad rough. also, it seems most have a slight misfire at idle, particularly with a fair amount of miles on them.
So other things to check or do would be the PCV valve and other vacuum hoses for cracks or leaks, valve adjustments, check the timing, try a fuel injection cleaning treatment like 'Seafoam' or have the injectors removed and cleaned, get the intake cleaned, get the idle fuel mixture adjusted if necessary and make sure the exhaust isn't leaking or clogged.
Start with the easy / cheap things first and work from there.
Or if the mechanic has a scope and exhaust analyser, they should be able to narrow it down, but it will cost more.

442man

Abecedarian,
This seems to be a problem aside from the rough idle. The miss occurs when the engine and truck are about the same speed with not much accelaration. Accelaration clears the problem right away.
Thanks for the info, I'll follow your suggestions.
Best Regards
Mike

abecedarian

I'd still look for any vacuum leaks, check the PCV valve, check the timing, do a seafoam treatment in the fuel tank and clean the intake (you can use seafoam or a good throttle body cleaner- search the forums here, there are discussions about how to do it). Then if it don't get better go from there, or come back here.