DanielTN

I have a 99/00 silverado. Its rebuilt from a rollover 99 with 00 body from a truck that had frame damage. Its extended cab 4 door 5.3 4l60 373 g80. The problem is im not sure what year pcm i have. I know the bcm isn't a 2000 because i cant disable the drls or program the locks like 00s can. I have no computer related lights but i do have a couple of problems with the running gear. I have done all the maintenance i can and inspected everything and as far as the outside of all the parts everything is bolted and wired up perfectly. My 2 problems which may or may not be related to the rebuild are these. The transmission, the 2nd to 3rd shift is horrible at anything but slight throttle of wot. It has a delay and clunks into gear. It doesn't feel like slipping, just like a crappy shift kit thats slow. Also while traveling between 50 and 60 in od with just enough throttle to hold speed it will by itself rev up a couple 100 for a few seconds and the jerk and the revs will fall back where it was running at. It will do this on flat highway with no throttle change. It feels like the tcc unlocking and locking back on its on when it shouldn't be. Secondly the engine pings on regular gas. Its a high gear low rpm ping. I have ran seafoam, cleaned the tb/maf, new fuel filter, new fpr. Higher octane helps alot but i dont like spending the extra money for it and i can still hear it a little. I guess this means the truck is running lean. Gm updated the computer but something i have been thinking about is, if they used the 00 pcm and the 99 engine. Doesn't the 99 5.3 use smaller injectors so the engine will be getting less fuel than the ecm thinks its getting. Just thinking about that but it might be off. Any help for me?

slowprocess

iTrader: (9)

Can't help you much, but I do know the 99 injectors were smaller. I had to replace my 99s with a set of 00+ when I went with the 02 pcm. I'm sure someone on here can give you all kind of reasons why things are acting the way they are. Good luck

DanielTN

How hard is the swap? Is that what accounts for the added horsepower in 00? The larger injectors and possibly better stock tuning? Did you have to swap your bcm? Anything else in swapping the pcms that makes it a problem. PS forgot to say hello First time poster. I have been lurking for 3 or 4 months so maybe i wont make any newb mistakes. Also is there a reason why i cant post in the classifieds. I have a few things a need but cant make a post to ask for them.