My Dodge Intrepid sounds like a diesel

My '99 Dodge Intrepid has recently been sounding like it has a diesel engine. Could it be that not all 6 cylinders are firing?

Also, I sometimes get a creaking noise when the heat is on. When I turn the fan off the noise stops, and the noise isn't continuous. It just makes this creak sound every once in a while. What's going on? hi. two seprate problems. do you have an oil gauge? with out futher information about your problem such as the noise the engine is making I can only say at this time that it is one of the following things that need to be pin-pointed.

1) bad valve train
2) very low oil pressure
3) bad connecting rod bearing or crankshaft bearing


you will need to determin if the noise is comming from the top of the engine or the bottom before I can tell you more. Hey I know your talking about a different vehicle but I have a 96 Mercury Cougar that started doing the same thing. Valves were rattling no matter what gas or additives I put in. I thought the oxygen sensors needed replaced. Took it to my friendly ford garage and found out that the sensors were fine. The said something to do with the throttle was gummed up and just needed cleaned and an engine flush. Car sounds like a new one now and gas mileage has improved dramatically. Hope this helps.Car Repair Talk's forum.