BlackNite3

I just checked the compression on my 1988 4Runner and have maybe 20psi of compression on the #4 cyl (middle, driver's side). All the others are fine (high 160s). I did a search and am going to try retesting it with oil in the cylinder to see if it is rings or valve related.

I noticed when I went to take out the plugs that the spark plug seemed loose. Would this have caused a "burnt valve" on that cylinder? Anything else I should look at?

I need the truck for the Winter when we have heavy snows (assuming this one is like the last two). Is there anything wrong with driving it on 5 cylinders long-term (through the spring)?

Thanks!
Patrick

TNRabbit

You need to fix it. Continuing like that can only hurt it.

You have a valve (or two) not seating properly.

And no a loose spark plug would not cause this.

BlackNite3

How big of a job is it to pull the heads on that engine? I'm changing the t-belt anyway so now would be a good time to do it. I just know the pace at which I work may prevent me from getting it done in time for winter.

Anything major I need to look out for?

TNRabbit

It's a PITA. There are dozens of threads here on the job with pics.