3 cylinders

[SR5_GT-s]

HELP!!!!! my stock GTS with the 4af is only fireing on 3 cylinders, being a diesel mechanic i have almost no idea what to do with this problem on a gasoline engine. only thing i know is it may damage the cat, i looked at the sparkplugs and theyre all fine except in the cylinder that isnt fireing, its black and coverd in carbon. could it be loss of compresion or a cracked head gasket over that cylinder? is it ok to drive? anny answers will be apreciated.

[Flashmn]

if its EFI, then its also possible that the particular injector isnt firing. Also check the distributor cap if theres a terminal in the cap thats broken, also check the resistance of the plug wire. Def, replace the plug (might wanna replace them all while you're at it).

and while you're at it a compression check wouldnt be bad either.

[REN69]

GTS never came with the 4AF... you sir have an SR5.

GTS ONLY came with the 4AGE EFI motor... never with a carb'd motor.