99 olds silhouette check engine light blinks.Engine is running rough and the smell of unburnt gas is coming from the exhaust.Also noticed a burning smell coming from between the engine and firewall.

indicates faulty/injector/s
run the fault codes to find causes for faults

Check the exhaust manifold from the engine bay to exhaust system

No flashing check engine light? I would say that unburnt fuel is being burnt inside the converter, melting its interior down.
The rough running could come from a misfire from one or more cylinders. The fuel which is not burnt in the engine, will burn off in the converter. Don t continue driving, it will ruin the converter.

Carol - if one of the pistons is not working, there is no combustion occurring in that cylinder. The raw, unburnt fuel is being sent to the exhaust, where it is burnt in the catalytic converter. *Very soon* the catalytic converter will fail as it is not designed to burn that volume of fuel. The catalytic converter is designed only to burn the trace amounts of unburnt fuel in exhaust gasses that may be present in a poorly tuned engine. This unburnt fuel is sensed (along with other related issues) and is on of the reasons the "check engine" or "service engine soon" light has come on.

You will probably not notice the engine skipping at high revs - as this is more noticeable at lower revs. You're also losing 1/6 to 1/4 of your engine's power. If a 6 cylinder engine - you're running on 5; and if a 4 cylinder engine you're running on just 3!

Not having this addressed *now* will only cause a higher repair bill for the catalytic converter later. You should repair or trade the car now.

Good luck!

Start with the simple things check for dead plug

service engine soon light flashing means the problem will damage catalytic converter if it is driven too far...possibly an ignition wire or spark problem causing the engine to run rough will cause raw unburnt fuel to enter the exhaust system

Bradley,
You have stated two problems. Coming to second first. Smell of burning rubber. in the car rubber is only at two places where it can burn, The tyres, unlikely as you have not commented upon your driving habits. Some people like to rev the engine so much before take off that the tyres go burning for the first few hundred meters. And then there is rubber on the wires and cables. You have to check the wires for any heat while the engine is running.
Coming to the first now. White smoke is generally of unburnt fiel and not oil. Oil alwayd give black smoke and that is the indication you get when the exhaust is giving black smoke. That means that the engine is consuming oil. if it is white then that indicates that the engine is cold and burning more gas/diesel. Is your a diesel vehicle?? But as you say it from under the hood. And that too behind the engine block. May be that the gasket is leaking from somewhere. If you could check the engine oil level for a few days early in the morning before starting the engine. If the level drops and the exhaust tail pipe does not blacken your finger when you rub it in it would mean that the oil is being burnt. Now what I suggest is that with the engine running and hand brakes on, go under the car with hood open and try to locate the source of the smoke. I am sure you would be able to locate it.
Then we talk again.

Needs a valve adjustment. I assume its EFI, eliminating the possibility of the carb.

I think the auto-lite plugs are probably your problem. yes it sounds like mis-firing. That's one of the few times the check engine light flashes. I'd suggest changing the plugs to a NGK plug, that's the ONLY plug we use in our Audi's and VW's (work at a VW/Audi shop). Try that, and it should take care of the rough running, if not, it will probably need coils too.

Sounds like you may need to inspect and replace your fuel line from front to rear. no other reason for your problem.