96 DeVille issues

[lawlert]

Two seperate, but possibly related, issues.

1) My gas mileage has gone down lately, from around 22 MPG to 17 . I use Sunoco 91 octane, keep the tires at 35 PSI (Goodyear Regatta 2's), and use 10w-30 motor oil. I usually drive 70 - 80 mph on the highway with the cruise on (I do have a heavy foot).

2) Car does not want to restart at times. I'll be in line at the drive thru, and I'll shut the car off if theres a long wait. When I turn the key, it fires up then dies a second later. Only way to get it to start is to give it some gas when it fires. If the car sits for some time, it then stats normally (was a pain in snowstorms when I would get out to clean windshields etc).

Now back in December, I replaced all the coil packs, spark plugs, wires, and the computer that the coil packs sit on because of misfires. I dont know if its any sensors that may be at the root of the problem(s), but I'd like to at least know what the right direction to go is.

Thanks!

 

[gambino1064]

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Two seperate, but possibly related, issues.

1) My gas mileage has gone down lately, from around 22 MPG to 17 . I use Sunoco 91 octane, keep the tires at 35 PSI (Goodyear Regatta 2's), and use 10w-30 motor oil. I usually drive 70 - 80 mph on the highway with the cruise on (I do have a heavy foot).

2) Car does not want to restart at times. I'll be in line at the drive thru, and I'll shut the car off if theres a long wait. When I turn the key, it fires up then dies a second later. Only way to get it to start is to give it some gas when it fires. If the car sits for some time, it then stats normally (was a pain in snowstorms when I would get out to clean windshields etc).

Now back in December, I replaced all the coil packs, spark plugs, wires, and the computer that the coil packs sit on because of misfires. I dont know if its any sensors that may be at the root of the problem(s), but I'd like to at least know what the right direction to go is.

Thanks!

my 96 cadillac deville use to something simeler aswell when i would come off the highway and would have to pay a toll both my car would shut off and alwas fire up instanly no gas so i chsnged the air fliter and i also blew high presure air where the intake goes rite to the engine it never done it again i changed my spark pulgs to the busch high perfourms and msn i love the gas millage i get i also but a after market in take with out a box just open fliter so the car can take in morenair and run cooler with less hot air around the engine again good milage with that upgrade but give it a shot it just might work