I've got a 2000 RX300 with 177,xxx miles on it. Last night the check engine light started blinking, the car started to run rough, esp at idle when in gear. Light is now solid. Error codes are as follows:

-Random/multiple cylinder misfire detected
-Cylinder 1 misfire
-Cylinder 2 misfire
-Knock sensor 2 circuit band 2

I have narrowed the problem down to cylinder 2. when I unplug the coil there is no change in the engine, unlike what happens when I unplug the cylinders. I tried a new coil hoping that would fix it. No luck still have the same problem.

I took it to a shop near my office today and they diagnosed it with low compression, possibly a valve.

When I get home from work tonight I'll verify the compression. Anyone have any thoughts on what I should check or look for?

 

Compression on cylinder #2 = 90, compression in others 180

Oh well it was a nice car while it lasted

 

Couldn't it just be a head gasket?
If it's a valve, I see prices for remanufactured heads ranging from $250-$450.

 

Does not appear to be a head gasket, still trying to decide what to do.

 

Leak down test & boroscope tomorrow to see if it is the valve or the piston.....

 

Leak down test confirms bad exhaust valve on cylinder #2. Boroscope shows a very sketchy piston in cylinder 2 as well. Looks like I will be ordering a long block since I put a new transmission & differential in this car about 3 years ago