Hi, i go a problem with a 96 cavalier auto 2.2l...The car run very rough at idle ( like if he run on 2 cylinder only) sometime it backfire at the intake... and it impossible to reach 20 mph with the car the engine is missfire... I check all the firing side of the engine ( coil, plug, wire) everything ok... i do a balance test on the injector everything ok...fuel pressure ok.... egr ok...i do a compression test ( 150 on all the cylinder).. i check the engine vacuum with a vacuum gauge and i got only 10 inch hg when its suppose to get 18-21 ing hg.. i check all the rocker pushrod .. everything ok....
i need some idea to what to check next or help if thats ever happen you.. do you think the timing chain timing can be bad? i dont hear a chain click....




HP sell car, Torque win race

Did you check the plugs for cracks?

sounds like the cat converter is plugged. unbolt the exhaust before the converter and see how it runs.



01 cav w/01 3400 gam gt 4t45e