Hey guys long time reader here! First time poster!

I'm having some problems with my 2003 S2000 API.

I have CEL light on and the car runs very rough at idle. Misfires under 2000 RPM and has 50 percent compression on C4. After 3000 it runs fine and seems good on power.

The motor has 120,000 miles on it and was bought 2nd hand from a military type. My guess is she's had a rough life.

Spark plugs and coil packs are all good. Just had a valve adjustment and it did not help. I'm hoping its a sensor issue but the guys at the shop think its a burnt valve.

I was hoping that one of you guys had some advice on where to start?

I would appreciate any help!

 

try a different set of injectors??

i had this problem in a single cam motor even though the injectors were spraying when i took them out for a physical look, it wasnt enough to compensate, when i finally changed it. it took care of itself (misfire went away)

what im trying to say is.. start small before you move to doing your valves.

 

could be a number of things. luckily, the head isn't all that hard to remove.

 

Injectors aren't going to bring back 50% of the compression one cylinder is missing.... It's probably a burnt valve if it's not obviously/visually burning oil.

 

Is it burning oil? Rings would start sealing better as RPM went up if the cylinder walls or rings were worn. Hopefully this is just a valve problem.

 

why don't you just do a compression test and leakdown test...it will tell you exactly what it is