I have a 98rt that is missing real bad while ideling and is sluggish under pressure. I rescently drove the car a long distance. The car got 114miles to a quarter tank of gas on the interstate, next day starting ideling bad. The next tank of gas 196 miles total. I changed the plugs and ran 92 octane and some cleaner through the tank. Didnt help. The car is firing on all four cylinders and drinking gas. What could be the problem? catylitic converter, timing belt, fuel filter, or o2 sensor.

Thanks for help in advance.

 

It's hard to tell just from the info you have given.Try taking the car to Advance auto parts or somehere you can get any stored codes read for little or no cost.
As a quick easy diagnosis I would say O2 sensors out of the four choices.A pick of my own would be plug wires (if you have them).
Repost the pulled codes when you get them and we'll tell you what to do.

 

The codes from advance were different than the codes from turning the car ignition off and on.

Advance Codes: 1390, 1492

Ignition Code: 12441155

My car battery light stays on because when the head gasket was changed everything was put back in the correct place. The machanics informed me that there had been an alarm on the car at some point in time and the box was still on the car that it was pulling from the battery but wouldnt hurt it. That is why the light stays on.

Thanks in advance for the help.

 

try replacing the distributer cap and rotor dont forget to put the grease in the boots ckeck the old cap for cracks and the rotor for a black dot if there is a black dot on the rotor you need to change if no dot wouldnt hurt to change anyway