I recently purchased a 1993 4Runner with the 3.0L (3VZE) engine in it. It ran rough and I'm having trouble diagnosing the problem. I pulled plug wires and determined that the #4 and #6 cylinders aren't firing.

Initially, I replaced the spark plugs and wires, but that didn't fix the problem.

When we were replacing the plugs, we checked the cylinders to see if it they were at least "popping" (as in having compression), and I seem to remember the #6 cylinder making noise like it had compression. However, we put a compression tester on it a few weeks ago and neither the #4 or #6 cylinders had compression - zero.

Can anyone point me in a direction to head? The motor doesn't make any noise, it has pretty good power for only running on four cylinders, and the plugs in the #4 and #6 cylinders don't have any oil or anything that would make it seem like the cylinders/rings are bad.

Could it be a problem with valves or the timing belt, should that be the next thing I check before I look for a new motor?

Thanks in Advance.

 

same deal on mine. i left it that way before i went on my deployment. i think it is an exhaust valve sticking on mine (only cyl6) but i will just rebuild the head mill and have a quality valve job done.

i guess the valve seats are hard to mill and need to be done by an expert, not mechanic joe at midas.

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i'd say burnt valves, if you've got no compression. Its a common problem and usually only happens on the 4th and 6th cylinder... And head gaskets are another problem for these motors.. either way you're gonna have to pull the head.