1990 Caddy Deville trouble keeping it on all 8


Asked by Sep 13, 2008 at 01:56 PM about the 1990 Cadillac DeVille Base Sedan

Question type: Maintenance & Repair

I have a 1990 Cadillac Deville with the 4.5. its been sitting for 5 months. Before it ran great better than ever. But when we tried starting it when spring rolled around it woul'dnt idol, would'nt run on all 8. so we replaced the Distributor cap an rotar.But it still had the same problem... i sprayed some carb cleaner threw the throttle body it shot out alot of black smoke an the it started running perfect on all 8. 20mins later i returned to see if it would work again but once again it would not idol for anything an sounded like it was only hittin 5 cylinders.I have spark plugs im about to put in. But i was wonering what else could be the problem? bad fuel filter? bad gas?

6 Answers


When you sprayed the carb cleaner did it run 'perfect' only while you sprayed it, for a short while after you sprayed it, or until it was shut down?

2 of 2 people found this helpful.

only for a minute, after i sprayed it

1 of 1 people found this helpful.

whenever you store for a long period of time any type of vechicle or anything that uses gas, make sure to get all of the gas out of the vehicle before letting it sit for months without use

1 of 1 people found this helpful.

Hmm... So it runs well after all the cleaner is burnt, or is it still running on the cleaner can you tell? If it's only running well with the cleaner in the system, I'd say you have a fuel delivery problem... likely poor atomization of the fuel due to the fuel deteriorating... If it runs for a while without the spray I'd think you have either a mechanical or an ignition problem... Bad compression/cold spark (Possible for various reasons If you have the ability check your spark and compression)... If you have a place in town that can flow test your injectors for cheap I'd take it to 'em see if that may be your problem. If you aren't using the car as a daily driver and you have the money you may want to think about sending the injectors out to be rebuilt... Even if it's not the cause it'd be a good idea considering the age of the vehicle. I haven't used 'em myself but I hear witchhunter.com is reasonable. I'll admit I'm kind a thumbing in the dark on this one. It's hard to diagnose from here, you may be better off just taking it to a shop to be looked at...


I find the fuel "deterioration" to be nothing but a wives tale, a myth by car gurus. 5 months is not enough time for a tank of gas to "go bad" sounds to me like possibly had some moisture issues or somthing as a result to leaving the car dormant for months

ethanol goes bad in a month. if you store a car, use premium gas (no ethanol in premium) at least. best to use stabilizer.

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