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Discussion Starter · #21 ·
A hard restart after sitting overnight might be a fuel pump check valve failing? If the rails & lines drain from sitting, the pump has the prime the system at the next start. This will be an extended crank-time to start. The check valve is serviced with the fuel pump, but I have seen in-line check valves spliced into the supply line.
One way to check for this is to roll the key to 'run'. you should hear the pump 'whirr' for a second. Turn the key off and proceed to then start the car. This initial priming of the fuel system may help starting.

It looks like the 3.3L to 3.8L was a running change during 1991:
View attachment 88514

The fillers:
View attachment 88513
The automakers were experimenting with recyclable plastics during this time, with mixed results.

Googling 'Mopar 5263102' & 5263103 showed some hits.
Sliman's shows both fillers. Inquire first.

View attachment 88515
Yeah I actually tried Silman's. Discontinued. I've found a few different dealers that use that same interface and for some reason they all seem to show all parts as in-stock for whatever reason.

I'll give that a shot on the fuel sending unit though!
 

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Since the ABS is taken care of the next thing I'd worry about is the transmission.
Look at the transmission computer. If it is a plain box, it should be upgraded. If it's got fins on the edge, it has already been updated. If you need to upgrade look for part number 4792122. Donor can be any 1990-1991 3.3 or 3.8 equipped car (Imperial, New Yorker, Dynasty) or minivan. it's plug and play.
 

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The failure to start will have nothing to do with the battery - if it's cranking over the battery is good.
That means either spark or fuel isn't present. Most likely it is fuel pressure bleeding off. You can experiment by forcing the car to build fuel pressure. Cycle the key from off to run (but not start) 2 or 3 times before trying to start. If this eliminates the problem then you know fuel pressure is bleeding off while it sits and that's why it's hard to start.
Hopefully it is the check valve in the pump and not the fuel leaking out of the fuel rail as new fuel rails for these cars do not exist.
 

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Discussion Starter · #25 ·
Since the ABS is taken care of the next thing I'd worry about is the transmission.
Look at the transmission computer. If it is a plain box, it should be upgraded. If it's got fins on the edge, it has already been updated. If you need to upgrade look for part number 4792122. Donor can be any 1990-1991 3.3 or 3.8 equipped car (Imperial, New Yorker, Dynasty) or minivan. it's plug and play.
Where is the transmission computer at?
 

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Where is the transmission computer at?
Passenger side inner fender. Here is what the updated one looks like (just an eBay example, not a recommendation to buy this particular one). If yours is missing those fins I'd recommend upgrading.
 
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Discussion Starter · #27 ·
Passenger side inner fender. Here is what the updated one looks like (just an eBay example, not a recommendation to buy this particular one). If yours is missing those fins I'd recommend upgrading.
Welp, found it! No fins.
Motor vehicle Vehicle Automotive exterior Gas Auto part
 

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The TCM is obsolete and un-upgradeable. Chrysler released a TSB #18-24-95 ages ago that improved transaxle shift quality markedly, among other improvements. See attached.
 

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Discussion Starter · #36 ·

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The biggest issue with shift quality is going to be when the car is really hot in stop and go traffic. The fluid gets warm and you get "bump shift" and rough down shifts. These often happen due to lower fluid pressure. Besides fresh ATF+4 fluid and a new filter, the updated TCM helps with shift quality in those situations.
 

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Some seriously good drugs.

I found the actual listing. Interior color combo is fantastic.

It's pretty much a brand new car. Love the color combo as well. Only grips I have about these cars are the tiny mirrors and the smaller rear windowshield.
 

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You are going to have to find people parting the cars out for the bumper fillers. No body pieces or trim is reproduced for the Imperial, not the 1980s ones either.
There are lots of areas of concern on these cars, so keep an eye on these things:
1) Transmission
2) Anti-lock brakes
3) Rear or 4 wheel air suspension
4) Fuel rail leaks
Especially that A604 transmission. If it works now, DON'T TOUCH IT, period. As long as the fluid is bright purple (it may still have the ATF3, you can safely top off with ATF4 if it needs any, it shouldn't unless there's a leak), leave it alone.
 

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The transmission gets a bad rap mostly because of people improperly using the wrong transmission fluid. Back then it relied upon ATF3 and now ATF4, no other transmission fluid should be used. It's otherwise rather dependable when serviced properly.
 
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