Logan

It really could be anything right now.... DI engines are kind of known to carbon cake the intake valves. I have 3-4 DI cars here and have never had the carbon problem that I'm aware of. I guess we are offering ideas on what it could be. Pretty sure you will need a scan tool to see any engine data....one of the parameters would show the fuel pressure. No way to hook up a gauge on a high pressure system. Pretty sure you will not find a fuel filter. You might find this link helpful.. http://www.underhoodservice.com/direct-injection-diagnostics-taking-pressure-readings/ .

Go look up 2003-2008 Toyota 2.4 L head bolts. Huge problem...typically the back 3 bolts (firewall side) pull up...Toyota has moved on. Those use the same M11 x 1.5 thread. Not that there is anything wrong with that....just the same. Your 2005 should be using a M11 x 2.0 thread. We do rent the Timesert kit for that.

A lot of DI engines suffer from it. Some think adding a catch can to the PVC system helps reduce it. Blasting with walnut shells is what I have heard of as a fix. Picture shows a pretty extreme case...a Audi intake valve.

Which 3 coils and why those 3? You really need a scan tool that can display misfires. Most cheap scan tools will not. Without being able to see which ones.....you are just guessing. Attached is pic of a GM Tech 2 displaying the misfire graph. Wifes Traverse just needed 2 coils on Sunday when she got home from out-of-town.....very clear to see on the Tech 2....2 cylinders with multiple misfires under load....one coil was noticeably worse than the other. To my surprise....took forever for the SES lamp to finally show a misfire code. (picture is old photo I have...not of the Traverse coils).

They rarely go bad. That sending unit is just for the speedometer. Do you have the code for the input speed sensor? That one is inside the transmission.

The hub on eBay has been sold....maybe they were the ones who purchased it. I have never worked on one of those set ups. Looking more at the service manual.....it looks like it uses a traditional replaceable bearing....and drum brakes. Hopefully....they are not being fooled by a cruddy upper hub bushing. Details are lacking...20 year old car....they certainly may have smacked a curb or something. Picture is 1998 Deville heavy duty 6 lug rear hub assembly.

Maybe this? https://www.oreillyauto.com/detail/b/acdelco-2729/wheel-bearings-hub-assy-seals-25107/hub-assemblies-25073/hub-assembly-12841/5a18a6d43148/acdelco-wheel-bearing-and-hub-assembly/rw2061/5978092/1998/cadillac/deville?pos=4 One on eBay too... https://rover.ebay.com/rover/1/711-117182-37290-0/2?mpre=https%3A%2F%2Fwww.ebay.com%2Fi%2F152285818489%3Fchn%3Dps&itemid=152285818489&targetid=478262996095&device=c&adtype=pla&googleloc=9013114&poi=&campaignid=1489270473&adgroupid=57569192116&rlsatarget=pla-478262996095&abcId=1139326&merchantid=101490027&gclid=EAIaIQobChMIxvWK19ja3gIVibfACh2o5Q7LEAYYASABEgJTs_D_BwE Looks like the HD hubs use serviceable bearings rather than the sealed units we have gotten used to. Bearings are easy to get. The part # will be stamped on the edge of the bearing race. They don't reinvent bearings.....there will be a size that will be a perfect fit and easy to get.

I would of thought someone would have chimed in on this. Anyway, here is a link that has the codes.. http://www.troublecodes.net/cadillac/fleetwood-5-7l/

Remove defroster grille to get to upper screws. Remove each vent to get to lower screws.

I don't think any owners here have ever had a Cadillac of that era. I cannot remember this issue coming up in discussion before. That said....it's a well known and common problem the flexible plastic bumper fillers would rot away on those Cadillacs. I still remember seeing them as a kid...the 2 rear chrome bumper fins out there all alone... 5 mph impact absorbing bumpers were a fairly new requirement in 1973. 1974 required the rear too. Failure of mid 70's types of flexible plastics? UV damage? Don't know. It sure didn't take long on those Cadillacs. There is a fairly large aftermarket industry making replacement filler parts for the Cadillacs. Several brands of replacements are available. I'm not sure anyone here would be able to recommend one brand or type over any other.

You might find this link helpful.....sounds like the same problem. https://sparkys-answers.com/2009/10/1997-cadillac-deville-erratic-high-idle.htm

Don't know...."94-97 were kind of bastard years....as GM migrated to OBDII.....Cadillacs lost a lot of the hidden features available thru the IPC. It was more of a question of is this GM vehicle OBDI or II?...a few GM vehicles had OBDII in '94-95.....What adapter do I need.....Do I need to use a VIM module.....etc. For me....it was never a question about using the IPC diagnostics...It was always "Am I going to use the Tech 1 or the Tech 2?" I always used a scan tool. A lot faster to do. 1998 and on.....it was very clear you were working on OBDII.

Most GM products....but not all older OBDI ones.... you can override the IAC using a GM Tech 1 or GM Tech 2. It has to be a bidirectional scan tool with the ability to turn stuff on/off to command the IAC. After OBDII......about '97..'98....pretty much everything had IAC control thru a GM Tech 1 or 2 for leak testing. Older cars without the scan tool ability to control...or if you have no bidirectional scan tool....you used the above Kent Moore tool.

They are the same thing. The IAC is just a computer controlled vacuum leak. There are several different ones used over the years. The rest of GM has been using these since the mid 80s. Only Cadillac was using the throttle control motor one. When OBDII came along Cadillac finally started using IACs. Has the intake ever been off? Could be cracked or leaking intake or intake gasket. Or leaking blow off relief valve. Bad gasket on either side of the "crossover" part. Leaking fuel injector O ring. Broken return spring on throttle body shaft or sticking cable. *The leak can be on the underside the intake....which you could never find by spraying around up top. Spraying around.....keep the spray liquid rather than vapor. If you find the leak the high idle will drop momentarily when you hit it with the brake/carb cleaner. ....and you should be able to repeat it every time you hit the leak. As mentioned.....starting fluid is a little too wild for finding intake leaks. I think you will have better luck with brake or carb cleaner.

Looking at my '93 Helm manual.....there is a 61 page section 6C. Fuel and air control system. Even more 6C info in the '94 Helm manual....60 pages for Northstar....63 pages for 4.9L. Both are 2 volume sets.....section 6C is in the middle of each 'volume 1 powertrain' manual.

The high idle issue is likely related to the the TBI being removed. Maybe wrong gaskets. ....Personally I use brake cleaner or carb cleaner to find vacuum leaks....IMO starting fluid is a little too dicey for spraying around. Some codes will not set if other codes are present. Its possible there are additional chewed wires. Or maybe a broken coil return spring on the throttle body shaft. Being a '96....the car will be using a IAC speed motor. Lacking a scan tool....There is a Kent Moore tool used to diagnose idle speed problems. J-37027-A. With the tool...you unplug the IAC....the tool works as a IAC driver. You can cycle the IAC open and closed independent of the PCM.....very easy to change engine speed with the tool. So if the IAC is cycled all the way closed (low)....and there is still high idle speed....there is a vacuum leak. There is also a noid light that plugs into the vehicle side harness. The noid LEDs will blink green and red all the time to verify the PCM IAC drivers are ok and are trying to control idle speed. The tool comes with 2 noid lights depending on which type of IAC you have....the square 4 plug version or the flat plug in version. Most of the time I use the tool to pulse the IAC apart to clean the shaft.

Curious.....I think Rockfangd asked earlier...... What exactly is this 'reman' engine? Was it in a crate or anything like that? Where did it come from? Does it look fresh? Has it ever been installed in a car? What was wrong with the original engine? Thinking maybe timing chain marks off or wiped out cam lobes...

There is a range of timing adjustment for the distributor. That range is often limited because of the vacuum advance and nearby obstructions. (intake manifold, firewall etc) If the distributor does not get 'timed' correctly with the engine.... within that range....you can get slow cranks. So you may have to pull it out several times.....and mess with the drive gear slot... to get it timed in correctly with the engine. You really cant just drop the distributor in and crank it up. You do have to fuss with them a little to get it set up right.

If the ignition timing is off it can do that.

On that era of Cadillac.....there is a engine ground that can get goofy. Cadillac has a service bulletin to dismantle and clean the ground. If i'm thinking clearly it is mounted to the engine block out front above the starter.

I am certainly not the expert... The biggest snag is the crankshaft is different. More details here about differences... http://www.northstarperformance.com/interchange.php

Couple of years ago I had two completely different family owned GM products do this in the same month. Fill it up with gas....no start / very hard start. One was a 2002 Saturn...other was a 2009 Traverse. It was the same problem on each.....a no code evap purge solenoid failure. Pretty sure both were under the hood and fairly easy to change.

A couple of fascinating pictures / diagrams of the famous chain can be seen here... http://www.toronado.org/forum/viewtopic.php?t=1511

It's obvious you had a infestation. They like to chew on wires. There have actually been some lawsuits due to automakers using soy based plastics for the harness. https://www.consumerreports.org/car-maintenance/how-to-protect-your-car-from-rodents/ Fisher posted the schematic.......splice S124......circuit 639......pink wires.