What component does engine code P1635B on a GM vehicle deal with?

Here's the deal on flashing AC on GM vehicles http://ricksfreeautorepairadvice.com/ac-light-flashing-gm-vehicles/

The 10243880 means it is a 95-99 350 V8 four bolt main crate engine. The letter K could mean it was built in St Catherines Ontario but the FKA is not in my list. And that may be due to it being a crate engine rather than an engine installed at the factory. The numbers are usually the month and date which would be July 16.
A GM dealer could tell you for sure.

2003 Silverado 2500HD REDUCED ENGINE POWER - Discussion on Topix

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Dec 28, 2009 - 20 posts - ‎12 authors I have replaced the throttle body, had the wires re-connected and .... The gauges all went wild and reduced engine power displayed on the dash. I looked it .... The truck just went to idle for no reason and it keeps happening. 2003 Chevy Trailblazer-CHECK ENGINE LIGHT AND ...
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Reduced Engine Power Message Displayed on GM Vehicles

www.underhoodservice.com/tech-tip-reduced-engine-power-message-dis...
Dec 10, 2012 - Tech Tip: Reduced Engine Power Message Displayed on GM Vehicles ... Model year 2008-'10 vehicles must have the engine control module (ECM) reprogrammed ... Do not drop the electronic throttle control components.

Speedometer and Odometer
The Vehicle Speed Sensor (VSS) is a gear-driven permanent magnet generator housed in the transaxle. The sensor generates a sine wave output with a frequency proportional to the vehicle speed. The Powertrain Control Module (PCM) converts the signal to an output that switches to ground at a frequency of 4000 pulses per mile. The signal (CKT 817) is used by various vehicle components. The signal CKT 817 drives the following components:
Is your check engine light on ? More then likely it's what is called a stepper motor ! This stepper motor is inside the instrument cluster behind the speedometer gauge an is electronically controlled ! They are fixable , gm has had problems with certain ones ! The thing I do is hook up a scan tool that allows me to check it an check for DTC'S - diagnostic trouble codes ! You could get one from a car salvage place $ 10- $20 , the whole instrument cluster !
Isi


GM Stepper Motor Replacement and Instrument Panel Disassembly

Bummer deal! Disconnect the negative battery cable for 30 seconds or so an reconnect it. This clears the codes and it takes several days for the computer to relearn. Then see if a code lite come on and check that out, if so. Did you gap the plugs properly? too wide or too narrow will trigger a code. A dirty combustion area results from your problem. I always use the product treatment at this web page to be sure its not residues causing your problem in one area or another. Hope this helps.
http://www.auto-tune-up-and-repair-options.com/Tune-up-Products.html

Most people will eventually learn how to get the codes

You use Google & Type: OBD & your codes

OBD P1728

Sometimes you need a vehicle or engine or year

If your looking for 1995 & earlier, you type OBD 1
or on something like a GM,just GM Codes or GM OBD1
& the code

CODES HAVE NOTHING TO DO WITH PARTS
Codes do not tell you what is wrong or what to do

Codes direct you to the system with the fault
Then you component test to find a problem

Without decades of knowledge & professional tools,
your not working on your own vehicles,except for the
mechanical parts

Well ya

You have to have a shop diagnose the code & component
test to find the problem & resolve it

We have had codes & obd systems since 1981 on GM & Ford
& every other vehicle worldwide since 1983

You have a vehicle that has a problem & fails to meet federal
emission standards,you know that, you have gotten the code,
now google the code & read up


The internet has pictures of how to get older OBD 1 Codes
& has a list for you of the sensors & problems

What engine ? could have come with three different one's ? 3.5 ,3.9, 5.3 LGZ is a RPO code - look at RPO sticker on your vehicle . Could be driver door jam ,glove box , maybe trunk .
LS4
Engine - Gas, 8 Cyl, 5.3L, SFI, ALUM, Cylinder Deactivation, GM
LZE
Engine - Flexible Fuel, (Gas/Ethanol), 6 Cyl, 3.5L, SFI, V6, Offset Bore, GM
LZ4
Engine - Gas, 6 Cyl, 3.5L, SFI, V6, Offset Bore, GM

Do not see LGZ for 2006 impala
LA1
Engine Gas, 6 CYL, 3.4L, MFI, HO, GM
LZE
Engine Flexible Fuel, (Gas/Ethanol), 6 Cyl, 3.5L, SFI, V6, Offset Bore, GM
LS4
Engine Gas, 8 Cyl, 5.3L, SFI, ALUM, Cylinder Deactivation, GM
LZ4
Engine Gas, 6 Cyl, 3.5L, SFI, V6, Offset Bore, GM
LZ9
Engine Gas, 6 Cyl, 3.9L, SFI, V6, Offset Bore, GM
L36
Engine, Gas, 6 CyL, 3.8L, MFI, HO, ERV6 Series
L67
Engine Gas, 6 Cyl, 3.8L, MFI, V6, Supercharged

Regular Production Option (RPO) codes that are available on the vehicle. The vehicle's RPO list is printed on the Service Parts Identification Label.

When mixing parts from different model year vehicles in the electronic age one never knows what will happen . Try it an see what happens .

Normal 0 Vehicle Identification Numbers (VIN codes)/GM/VIN Codes
GM has traditionally encoded the platform as the fourth character of the VIN. Other content includes an engine code the eight character, model year 10 th character and so on.
Take note of the eight character and call a GM dealer.

The vehicle until warm runs off a different set of parameters for the computer as far as timing and fuel are concerned. Temp is not a problem at 200... and it is normal for the oil pressure to lower once warm. ( as long as you have 10 psi oil pressure for every 1,000 rpm's you are ok.)

The two codes cam/crank sensor are timing related related. So I would suspect something that deals with both sensors,Timing chain maybe?This particular engine has a problem with chewing up timing chains. If you find this to be the problem i recommend using factory GM replacement parts. I have had to re-do several that i tried to use aftermarket parts on. The only other thing that comes to mind , dealing with the drive ability, is the fuel pressure. These vehicles are sensitive in the fuel pressure area, but this should not make the light on the dash come on. You may have more than one issue. The other part of the vehicle that deals with timing is the ECM. If you have access to a scan tool with data stream on it , you can look and see if the ECM is receiving a signal.