Toyota Repair: 1999 4cyl toyota camry, air fuel mixture, hydrocarbon emissions

Question
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Followup To Will a leaking valve result in high CO2 and hydrocarbon emissions on a vehicle inspection test?
Question -
I have the above 93k mile vehicle.It has a rough idle yet never stalls.The compression readings are cyl 1.150lbs cyl.2.200lbs cylinder 3.200lbs and cylinder 4 90lbs.It burns no oil.Coolant is not apparant in the crankcase oil.No leakage of any fluid is exhibited externally.No oil is on the plugs.Please advise in sufficient detail.Thanks
Answer -
The rough idle is caused by the low compression in the #4 cylinder, and by what you are telling me it sounds like there is a leaking valve, either intake or exhaust, in either case the cylinder head will have to be removed and it will probably need to have the valves ground and replaced as needed.

Answer
The HC emissions will be way too high(HC is unburned fuel) it's high because of incomplete combustion, the CO is not affected that much, high CO is caused by a rich air fuel misture, incomplete combustion takes place when one or more cylinders has a misfire, it can be caused by low compression or a non firing spark plug, instead of the fuel air/fuel mixture burning completely some or all of the fuel does not ingnite and is pushed out of the chamber into the exhaust and shows up as excessive hydrocarbon emissions.