98 eldorado starts, runs rough and backfires. All codes have been cleared

any codes,tune up,air filter,check coolant level,camshaft sensor,could be coils,fuel filter should be OK gas smell.

hi Jhlightcap.

The Common Problem: Rough Running Engine

A properly-operating engine should run smoothly and without excess noise. If your engine starts operating in a manner that gives you the perception of "running rough", it is likely due to a handful of common causes. A mechanic would investigate these common causes first in order to rule out a simple explanation for the engine's unsatisfactory operation.
The common causes for rough running in an engine are:

• Engine miss
• Vacuum leak
• Dirty fuel injectors
• Carburetor problems
• EGR valve
• Ignition coil
• Spark plug wires
• have a look at this link.

Rough Running Engine James on Engines 2

Why would you tell anyone that?

Check for codes

You know the check light is on & is where you start

There is no resetting a check light
All your doing is clearing all data needed to diagnose
any issues

P1391 DODGE - Electronic Brake control Rough Road Data Unusable/unreadable
You need to see the dealer on this, it may be programing issue.

all code readers will retrieve information stored while in the on position --doesnt need to be running ---when you rehook up scanner either resubmit or edit request with codes

needs crank sensor replaced

oxygen sensor in exhaust

You should get the codes checked and start from there. My Kia Sportage was also backfiring and running rough, after checking the codes. It had misfires on two cylinders. I did a tune up and had to replace one of the ignition coils. Now it runs great!

I have a 1994 Cadillac Eldorado and every time i start it the car has rough Idle and the Idle fluctuate's. I also can feel it in the gas pedal when the car is doing this I tried replacing the throttle body sensor but it still does it I also was told it was the Idle error sensor. So instead of spending the unecessary money again I thought I would go online and see if anyone could help me with this problem.

Sounds like the alternator isn't running good, have you tested this? Perhaps it isn't sparking cosistently and the loss of power would be explained if it isn't kicking out enough power.