latinmustang90

I got a 1990 mustang gt and idles badly the all engine shakes and my check engine is on I check the codes and I get this 34,63,85 with the engine off and with engine running , 98 ,63 but it seems to run ok exept when Idles and smells like exhaust please help !

rdmypny

do you have a way to decode that? if not if there is an autozone around they will do it free could be a large vaccume leak, plug or wire bad, o2 sensore if equiped, if it has always done it since you got it it could be a cam (highly doubtful)

mjr46

you have a misfire, that's why it has a rough idle, vaccum leaks will cause a rough idle, also defective ignition components such as a bad cap, rotor, wires or plugs will do such..has it had a tune up recently??

latinmustang90

I change wires and spark plugs today and still doing it it seems to performe ok when is running the problem is when I stop it feels like a earthquake everything shakes .when acelarates too ...

mjr46

perform a compression check and make sure all cylinders are good, or with a insolated pair of pliers pull the wires one by one on the cap noting which one does not affect load change when pulled, the one that does not affect load change when pulled will be the prob cylinder, or run a koer/cylinder powerbalance test using the ecm function to see which cylinder is not contributing power

mattdel

coil chargeup could be gettin slow.. how old is the coil

latinmustang90

i got 12 years with this car and I had never replace the coil or the ignition module just basic tune ups

latinmustang90

how can I check for vacum leaks ?

mjr46

use a can of carb cleaner and spray around all gasket surfaces and vaccum lines and listen for the idle to change / smooth out to indicate where a leak is

latinmustang90

thanks appreciated all your help I would try that and see what happens thanks ! = )