i have a 91 deville. i replaced plugs wires cap and rotor. it still runs rough at idle and at light throttle going down the road. if i give it more than half throttle it runs good. it shutters pretty bad. if im going any speed and just go light on the gas it does it. hard on gas and it runs good. any suggestions would be helpful.. thanx

 

How did car run prior to tuneup? How often is car used?

 

i just bought it. it ran a lil worst before tune up. its not on the road yet. ive been working on it. i just need to figure what the prob is

 

Are there any codes? Verify firing order and check timing is correct. Check fuel pressure. You will need Factory Service Manual (FSM) to learn how to use On Board Diagnositics to fix your car.

 

i havent checked codes yet. firing order and fuel is good. can i use a jumper wire on the diagnostic connector to check codes or need a code reader? timing is good also. oh and the check engine light is not on

 

i used the onboard diagnostics and this is what it showed..8.8.8, e52, e98, .7.0, f.8.5, f.8.0.. how do i clear the codes..again this is a 91. oh and this problem gets worst the hotter the engine is

 

any ideas?

 

well after reading some posts in here i tested the injectors. i had 4 that read less than 5 ohms and 2 that read less than 2 ohms. only 2 were in good range. so i will replace them and hopefully thast the problem..