I have a 2007 grand caravan with a 3.3L v6 and 123000 miles on it. The problem started a few weeks back it would crank run rough and die. This would repeat several times then it would crank and run fine. I got some codes that indicated the cam shaft position sensor was the problem so I replaced plugs, wires, coil pack, cam and crank shaft sensor.

There was a dead misfire on the number 2 piston, I slipped the valve dover off and found a broken rocker arm. I replaced that but mis was still there. I pulled the heads and found a bent intake valve. I bought a new valve had the heads reworked, and put it all back. The vehicle ran fine for 1 day. I went to town did several errands came home and it sat overnight. The next day, it would not crank! I slipped off the negative battery cable, cleared the computer and then the vehicle started but appears to have a misfire again.

I never got a code for the PCM but I am beginning to think it is the root of all my problems. Can anyone tell me I am wrong?

 

Is it possible for a malfunction of the PCM to result in a bent valve?

 

I bought a computer from a salvage yard for 65$, contacted a company (carcomputerexchange) in North Carolina that will reprogram for 100$ plus 10$ shipping. My local dodge dealer wants 85$ but the computer has to be in the vehicle. That would be a big problem for me to haul the vehicle to them. They told me the camshaft position sensor nor the PCM should cause the vehicle to bend a valve. I am worried that I could have a timing chain issue. All my past experience with this has been when the timing chain goes out that is the end of the line. I just don't know????

 

PCM bend a valve? Maybe theoretically but how do you prove it? You and I couldn't and I'd venture to say even a dealership couldn't. Set it up in a lab and you may.

Companies unaffiliated with Chrysler Corp. have been programing PCMs on a bench for Years. Interesting question to the dealership would be why are Chrysler dealerships so far behind the curve? Good bet we all know that answer.

I have read both the 3.3 and 3.8 ltr engines are non - interference free wheeling engines.

 

If the misfire, broken rocker arm, and bent valve are all occurring on the same cylinder I have a hard time accepting that the PCM, cam sensor, or even the timing chain are the culprit.

Thinking out loud I wonder if there's something wrong with the cam lobe, valve lifter, or a blocked oil passage for the lifter (is that even possible?).

 

A worn cam lobe would misfire until the cam was replaced. This car worked just fine after the heads were reworked. One thing I forgot to mention was several push rods fell out from under the rocker arms when the valve was bent. I am hoping that is all that is wrong now! I do not want to have to pull those heads again. A lot of work and costly! I am taking a few days to think on the matter and waiting for the computer to come in. The PCM I ordered comes from a Town & Country wrecked from the rear with 80000 miles. The salvage people gave it an A+ rating.

 

Several push rods fell out when the valve was bent? That doesn't sound right unless you mean when you pulled the head.

As for the misfire returning - you don't mention if there are any new codes stored?

 

on 4/14/13 there were no codes
on 4/10/13 p0607 control module performance
pending p1607 poweertrain control module is reporting internal errors!
on4/21/13 ISO9141, KWP2000, Linking Error.
so I used the key on off and got p0513, incorrect immobilizer key
performed a cold boot
I also got misfire codes on cylinder 2 and cylinder 3 at different times.
At the present time there are no codes and the check engine light is not on. However it is missing on at least one cylinder. I slipped the valve cover and found a broken rocker arm on number 2, also I pulled the the back cover and a couple push rods were not under the rocker arm. This is when I decided to pull the heads.

My PCM was delivered today, I will now send it to North Carolina to have it programmed.
I am not moving the vehicle, will not crank on it. I hope that this mis is due to push rods dislocated, If I have to pull those heads again, I am going to think up some new curse words!

 

I thought about putting new lifters in but decided it was not necessary. I hope I was right.

 

So when you pulled the valve cover off to investigate and found the broken #2 rocker arm you found that a couple of other pushrods were not under the rocker arms on the rear head before you touched them? Crikey that sounds pretty worrying to me. I think this is past what I know about the engine's internals from experience as I've never pulled the pushrods myself, but as far as I know there is no way for the pushrods to become displaced providing everything is in the correct position and torqued down.
Did you inspect the pushrods for damage to the ends and any bending? The factory service manual specifies the pushrod length as being 135.438mm (5.33in)
While the heads were off did you inspect the valve stems for damage? Did you measure the valve length to verify that they were not damaged or shortened somehow? The spec for those is:
125.84-126.6mm for intake valves with a stem-tip height of 48.1-49.7mm and a diameter of 6.935-6.953mm
127.2-127.96mm for exhaust with a stem-tip height of 48.53-50.09mm and a diameter of 6.906-6.924mm

As for the codes and the misfire, I am now more confused than before about the timeline but I think you have an underlying mechanical issue that needs to be sorted out first, then you should evaluate whether the PCM is indeed giving you trouble. P1607 and P0607 can be caused by low voltage so unless they are persistent and repeatable I would be tempted to ignore them for now.

After re-reading your original post I have a couple more questions:
You changed the plugs - the new ones would be Champion brand double platinum plugs, correct?
Were the new coil packs OEM or aftermarket?
How did you gap the crankshaft position sensor?