1994 caprice 4.3L V8 engine problem

I have a 94 caprice classic with a 4.3L V8 and here is my problem.
The car will start and run ok when it is cold, but as it warms up the timing advances up and up. Then the car has no power(it will not even move) and it back fires the lifters rattle etc.......
It all started out when the drivers side catalitic converter went bad.
The part list goes as follows;
EGR valve- new
exhaust all from the manaflod back- all new
PCM- new and reprogramed
ignition control module- new
ignition coil- new
o2 senser- 1new 1 old
But the car still thows an error code of 42, and the timing still advances even when the car is at an itle.

CAN ANY ONE HELP ME?????????????????

check your idle air screw on the throttle body,
it coud even be your throttle body positioning
sensor. i had a 91 camaro that done that
same thing mine was the throttle body
positioning sensor.

Thank you but that has been check and does not have to do with the timming advancement.

4.3 v8??? the 4.3 is a v6

They both exist. But the 94-96 Caprices did come with a 4.3 V8, 265CID I think. Basically the same engine as a LT1, just a smaller displacement.

While it is a V8 at 4.3L, it was not an LT1. Check out http://www.9c1.com/brochures/index.html
for statistics almost every single year of the Caprice 9C1.

I have the same problem. I spoke with some people and if I don't do the work it's gonna run me around $800 dollars.:banghead: <<-----Me while on the phone with the Cadilliac Dealership, after speaking with my mechanic.

After I looked for the prices of the parts myself in my Chevrolet Classic Industries Parts & Accessories Catalog for the parts have accepted the dealer amount seeing as though the motor is running great now and plan to rebuild the tranny in the spring.

o yea I have a 1994 Chevrolet Caprice 4.3L V8 and a couple of people have told me that the motor was built similar to a corvette motor.

The 4.3 is the "baby LT1". I think it was just destroked

Yes, it was referred to as the "baby LT1" - it was more than destroked, it was also debored over the 350. It has the 305 (3.74") engine bore with the 302/283/265 (3") stroke. It had the same engine management system and induction/ignition systems of the LT1 as well. RPO number was L99.