Geo metro has 270,000 km. It just has started to run very rough. Checked spark plugs and timing and replaced wires cap and rotor. Currently running at 12-14 BTDC. Don't know if this 92 metro has TBI or carb? I have yet to do compression check. And , by the way, there is an oil leak!!!

New timing belt 60,000 km ago.

What is the most likely reason for rough idle in this case?

What are these engines famous for at this mileage? Will rebuilding the head be enough or will the rings need to be done as well?


I have only worked on this car for 15 minutes and do not have a manual.... so until I can get to a library, I need to hear from all of you and your experiences with these engines.


Thanks

Sounds like the exhaust valves are on the way out. Usually, #3 first, then 2 then 1. By the time 1 is going, it will not start due to no compression. This is very common. I would recommend a re-ring also since the it seems when you do the valves the compression is restored and the motor will have blow-by.