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Reggie Whiddon
Reggie Whiddon,
Category: Chrysler
Satisfied Customers: 166
Experience:  Lead tech at river regions auto
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Customer Question

Please don't answer this question unless you REALLY know these 3.3 Ltr enginesSorry but I've asked questions about this a couple of times and I'm getting nowhere.


I have a 2005 Chrysler Town & Country van. The engine overheated due to a leaking radiatorIt was run for a couple of weeks just refilling the antifreeze tank. The engine finally overheated and cracked one of the heads. Stupid Ah !


We replaced both heads the thermostat and radiator. It no longer overheats but it's got a misfire.

We tested the fuel pressure and vacuum which both seem to be correct. So far I've replaced the following to cure the misfire:

Spark Plugs (Champion installed)

Plug wires

Coil Pack (Twice)

EGR valve

Idle control sensor

Both 02 sensors

Cam Shaft position sensor


MAP sensor

Right now it’s running, missing and throwing up P0135 02 sensor code. Now I’m being told that the computer may need to be flashed by the dealer.

Is this correct or can you make any positive suggestions before I run this thing behind the barn and shoot it.

Submitted: 1 year ago.
Category: Chrysler
Expert:  Reggie Whiddon replied 1 year ago.

Your not throwing a misfire code do you know which cylinder is misfiring? I would suggest a running compression test, take a plug out one at a time and check compression with engine running, so we can rule out internal engine failure

And I know of no reflash that would fix this

Customer: replied 1 year ago.

Well at least you made me smile... We are doing a compression check right now. I've got to go for about an hour but I'll get back to you... Thanks for the answer.

Expert:  Reggie Whiddon replied 1 year ago.

Your welcome I will be checking in

Customer: replied 1 year ago.

Okay we tested the compressions. They range from 105 to 108 pounds. Okay I think?

Expert:  Reggie Whiddon replied 1 year ago.

Little low but that's okay is that running compression

Expert:  Reggie Whiddon replied 1 year ago.

You mentioned the vacuum was good what is your reading

Expert:  Reggie Whiddon replied 1 year ago.

Is your misfire constant

Customer: replied 1 year ago.

Yes that was running compression. I'm told the vacuum was bouncing a little around 15 to 18 inches. I don't really understand that but it's what I'm told. The fuel pressure was between 58 - 66 pounds at the rail.


Expert:  Reggie Whiddon replied 1 year ago.

If the needle is bouncing therr is your problem. YoU should have a steady reading

That bouncing is indication of a valve problem did you have heads redone?

Customer: replied 1 year ago.

I don't really know how to answer, is it consistant. I can say that it seems worse at low revs, it seems to run smoothly for the first 20 seconds when the engine is cold. The engine seems to stutter giving little shakes every now and again as it misses. I'm trying to describe what we have going on here...

Customer: replied 1 year ago.

Yes they were rebuilt heads. Ill re-test the vacuum myself. I'm being told that the vacuum didnt so much bounce so much as change when the engine was sped up.

Expert:  Reggie Whiddon replied 1 year ago.

The flucrusting needle on your vacuum gauge is a valve do u have any valve train noise at all

Customer: replied 1 year ago.

Let me retest the vac and I'll get back to you...

Expert:  Reggie Whiddon replied 1 year ago.

Fluctuating sorry

Expert:  Reggie Whiddon replied 1 year ago.


Customer: replied 1 year ago.

Okay the vacuum is steady at 16 1/2 pounds at idle. It alters as the motor is revved but comes back to 16 1/2 again if the motor revs stay the same at say 2000 rpm. I hope I'm making myself clear.

Expert:  Reggie Whiddon replied 1 year ago.

Okay that's good news but that vacuum is a little low

Can you give me some readings of scan tool data such as fuel trims, map, tps

Expert:  Reggie Whiddon replied 1 year ago.

Okay in researching your problem I see why you were told u needed a reflash. For thr 02 sensors bt again I say that want fix a misfire have you tried killing cylinders one at a time to see where drop is

Customer: replied 1 year ago.

I'm at home and the car is at my shop so I cant do anything with it right now. It doesn't seem to be one cylinder but more of a random misfire.

I had a thought... Going back to when this started, the radiator leaked and over heated the engine. A head cracked and allowed antifreeze into the cylinders. From there the antifreeze leaked into the exhaust system. Now this is a taxi and covered a lot of miles leaking like that. I'm just guessing but probably a couple of thousand miles, maybe more. Could this antifreeze have damaged or blocked the catalytic converter causing back pressure and the misfire ??

I've never had a bad cat before so I really don't know much about them or how they fail...

Expert:  Reggie Whiddon replied 1 year ago.

Okay I didn't know it was a taxi. About the cat in theory you are dead on and if it was driven under those conditions you can be certain it needs replaced. But it will not cause your problem as I understand it. To me when u say misfire Im thinking a dead cylinder either constant or random such as with a bad plug or wire, it could be described as the feeling of a fish biting your line, like a jerking. This may not be what your having because interesting enough we have no misfire codes.

The only code you have is for an o2 heater.

When a converter stops up it want give you the feelin g of a misfire, Ill describe it like this, imagine if your car was running great, now say I come over and put a stop on your throttle and u only have 20% of your throttle. YOU Would have No power

Now here is another to support your theory your vacuum reading. Remember I mentioned it was low that happens when cat stops up. The easiest way for you to check this is remove both of the o2 sensors th at are before the cat and drive it see if it improves

Customer: replied 1 year ago.

I've been trying to diagnose this van for weeks now and I've come to the end of my rope with it. I just booked it into the dealership for diagnosis for $115.00 next Tuesday.

I'll go ahead and pay you for your help and get back to you with the final outcome just for your interest...

Thank you for your help,

Tom Elliott

Expert:  Reggie Whiddon replied 1 year ago.

Well thank you sir but we just got started I will be excited to hear the outcome