Need a long mystery solved

intrepid

#1

I have a 2004 Dodge Intrepid (2.7 liter engine) with about 144,000 miles on it (mostly highway). Over the past year or so, the check engine light has been on due to a P300 code (random misfire). This has caused the car to “hesitate” a bit when using the accelerator for the first 3-5 minutes of driving (it seems to be OK after this time period). After using a few non-dealer mechanics, and now just recently a Dodge dealer, they are still at a point where they can’t quite figure out 100% what it could be. They’re next best guess is to get in and take a look at the timing chain to see if it is stretched (which I guess is about 8 hours labor plus cost of parts). I have already had new plugs, wires, ignition coils, all four O2 sensors, cam sensor, crank sensor and new solenoid put in. The dealer has checked the fuel injectors (swapping them on each side) and the misfire still comes from the same side so the injectors are good. And he says the fuel mixture reading is just fine so he strongly feels that it’s not the fuel pump. So, after spending $1500 or so (over the past year) on a car I bought for $3500 in Nov. 2007, I am wondering if another investment of $1000 or more for the timing chain investigation would be worth the risk. Has anyone had an similar problems with 2004 Intrepids. The dealer mechanic said he is as frustrated as me. I doubt it. Thanks for any help in solving this mystery.


#2

"After using a few non-dealer mechanics, and now just recently a Dodge dealer, . . . “
”[Their] next best guess . . . "

Key Word: Guess

That’s a shame spending all that money on guesses and still the problem persists. I wish I got paid good money for mistakes I make.

Throwing parts at it didn’t work (“I have already had new plugs, wires, ignition coils, all four O2 sensors, cam sensor, crank sensor and new solenoid put in.”).

What else have they checked besides the injectors and with PO300 - random misfire, how did they determine the “misfire still comes from the same side . . .” ? Where on that side ?

Has anybody checked the compression ?

CSA


#3

CSA is right on about all of that, including the questions. Personally I wouldn’t do another thing until the compression was checked.

Another question would be whether or not it was checked for vacuum leaks. Has anyone, for example, put a vacuum gauge on it? Special attention should be given to those things that can act like a vacuum leak - e.g. the EGR system.

I would also hope that someone checked the fuel pressure with an actual pressure gauge - rather than just looking at fuel trim values.

Was it those 2.7L Dodge engines that were rolling disasters? I don’t know much about it - I just have some recollection of Dodge having a 2.x L engine that was nothing but bad.