1990 Century won't keep running

I just bought a '90 Century in what looks like fantastic condition.
100K Florida car, no rust, ice cold AC very clean and solid.
3.3L w OD auto trans
New oil change, new shocks & struts to put it right for using daily.

The engine cut out on the highway - a little balk then died (as if out of gas)
Little while started re-started okay but died again minutes after that.
Since then I replaced the fuel filter, the fuel pump, one of the relays (tried it in each of 4 relay spots to see which one might be bad)
No change in symptoms - starts when cold then dies a few minutes later.
I also tried taking off the 4 wire connector at the top of the trans case (just under the air cleaner) I believe this to be the TCC switch which I read can cause these symptoms. No luck.

I got a code reader for OBD1 and got these codes - 12, 28 & 29.
12 means diagnostics are working properly
28 = 3rd gear switch OR quad driver module OR trans fluid pressure switch open or short
29 = 4th gear switch OR quad driver module OR secondary air injection system - circuit problems

Help? Thanks in advance.

Welcome to AF!!

I would replace the crank position sensor as it sounds like that is the issue. It will not allow the engine to start and run if it is bad. You should be able to determine this if there is no spark from the plug wires. One of the common symptoms of this sensor going bad is that it will start and die after it gets hot. Unfortunately I don't know where it is located on the 3.3,

I need to understand this better.
The crankshaft position sensor has a code - 19
I'm not getting that one.
Could a faulty crank pos sensor damage the quad driver module?
I appreciate your help on this.

Not usually. Here is some information that may help you diagnose the quad driver issue:
http://www.troublecodes.net/articles/quaddriver.shtml I didn't link is so you may need to paste it into your browser.

Check the CPS just to be certain that it isn't bad as all the symptoms fit but it may only be part of the problem that is totally unrelated to the light.

Had similar situation, my mechanic said my ECM had went out, changed it, but then it would idle but not accelerate. Checked everything, injectors, ICM, fuel reglator, fuel pressure, CPS, changed ECM again, same thing, we are stumped. Oh my mechanic...35 yrs. + exp. & has scrached his head on this one