1.5 misfire..head work.
 

My lady's 97 Protege LX 1.5 has a pretty bad misfire. She has had it for about 5 years now, no major problems, other than the cat had to be replaced (under warranty) when it was first bought. Got it at 64k miles, have done most of the PM.. blah blah anyways

The misfire has gotten worse over the years, now it is at 130k miles. I'm thinking that whatever caused the first cat to go out has transpired into this very rough misfire that is the worst at idle, can feel it through the whole chassis and straight through the steering wheel. It dissipates after about 1,200 RPM.

Obviously, fuel isnt being burned properly; the MIL came on about a year ago, pulled a p0300 (random multiple misfire) and a p0303 (cylinder 3 misfire) but took it to my school auto shop and cleared it. Did a dry and wet compression test, from what I remember, cylinder 3 was reading 30 or 40 less than the others. Checked wires, plugs, all that good stuff. Found nothing.

I would like to pull the heads and see if I can figure what is causing the misfire. I'm thinking a burnt valve or valve seat.. are these seats the replaceable press-in type or are they permanent? Because damn, we really can't affort to get the head machined:(

The other thing im thinking is possibly a bad ring, but its odd that the light hasn't come back on since I cleared it. I would think that the misfire monitor would have triggered a code if it was the rings, OR even the valves, but obviously something is causing the low compression on cyl. 3.

I am getting the full gasket set with the valve stem seals, so its gonna take a good minute. Should I buy the new head bolt set? Will they snap if I don't? Also, since there is no adjustment screw on the rockers, guess I have to use shims for the valves? where do I get these from? Do I need a special tool? I would greatly appreciate any honest help I can get, as I really need this car to last a while longer.

Any leads, or help? I could definitely use some from someone who has done this engine before.:eek: