2004 Dodge Intrepid - can't figure what's wrong

I have a 2004 Dodge Intrepid SE (2.7) with 138,000 miles on it. Over the last six months the check engine light came on and off for a few days at a time. Then, recently, it started flashing so I took it in to have it checked. First they replaced an O2 sensor, good for a few days but then check engine light came on again. Showed it was misfiring so replaced sparkplugs and wires and also replaced the second of two 02 sensors. Codes cleared but light came on again after a short time. Replaced all six ignition coils but again after driving for a short time, light on again and flashing. Mechanic is trying to figure out what to do next as nothing is showing on the codes. Car seems to have no power when I hit the gas pedal, just hesitates and won’t go faster than 35 or so. I heard there was an oil sludge problem in some Dodge Intrepids. Could this have something to do with the problem ? Thanks for any help. Mark B.

It would be a great help if you posted the actual codes. I also think that you need a new mechanic. So far this looks like shooting in the dark. All of these codes have diagnostic procedures to go with them - to avoid throwing parts at it.

Mark, I Believe Your Intrepid Is Too New To Be One Of The “2.7L Sludge Engines”. Newer Models Were Corrected By Chrysler.

I think your mechanic might just be in “over his/her head”.

CSA

Thanks ! I was hoping it wasn’t the slug and I think someone else told me that the 2004 was fine (only earlier ones were the problems). I may take it elsewhere now.
Mark

Yeah, your mechanic seems to be a parts-replacer rather than a diagnostician. To say “nothing is showing on the codes” is dead wrong as all codes say something about the problem. Maybe you could share with us the codes. Based on your description you could have anything from a sludged engine to a torque converter problem to a restricted exhaust system, or a number of other things. Share the codes you have received.

Have the fuel pressure tested. If the fuel pressure isn’t up to spec it can cause engine misfires, which causes the Check Engine light to start flashing.

Tester

Good Advice, Tester. Also, Fuel Starvation Is A Possible Reason That “Car seems to have no power when I hit the gas pedal, just hesitates and won’t go faster than 35 or so.”

Could it be as basic as a fuel filter?

CSA

I have worked on this same problem for months, possible other codes are po172, po174, po175
changed the fuel pump, tps and all 4 o2 sensors it now has a bad transmission, never did figure out why the check engine light came on. Good Luck.

A faulty MAF sensor can cause this kind of trouble along with vacuum leaks after the MAF.

Does this engine use a MAF? I thought Chrysler used MAP sensors instead.