I know you all hate it when new people repost a problem that has been solved in another thread well out of the the ones I read nothing seems to be my exact problem

Alright I have a 1999 Sierra w/5.3 with 200k+ miles on original everything except fuel pump (has less than 6k on it-walbro) fuel filter (7k), Plugs (autolite), wires, injectors (updated to 02 5.3 44k)

well *** stated it starts rough as hell.... It sometime takes about 10 secs to start up...and then when it come off warm up mode it has a rough idle like its cammed... its been doing this since mid march ... so I figured it was the injectors being to big for the tune and I have bad rear o2s. so figured really rich

So I call up Nelson this past week get my tune, I get it in and its starting to run stronger and stronger while driving it around well I now have about 150 miles on the new tune SES come on get it scanned it said "o2 sensor rich- 2" and it still starts rough as hell and choppy idle

I had Allen tune it for the updated injectors and update to the 02 tune with it running the 91-93 Oct. Removed the rear o2s so I can cut the cats and remove the EGR for my headers that I dont have yet!!! Would this cause un issue (EGR)? having hot gases going back into the intake?

Now would my o2 sensor go bad from my motor being so rich for so long and I probably cut the life of the plugs pretty good also? (if anything like a 2 stroke?) Ive cleaned the MAF with a half can of that electrical cleaner, no change.... cleaned the throttle body still nothing, did the catch can mod, I have yet to try the carb or brake cleaner around the intake to see if theres a air leak, also plan on checking the regulator on the rail (tomarrow ill check)
I hope its not a compression issue?!

Ive been looking into the NGK tr55s ....wheres the best place to get them from? NAPA stock it?

How about those O2s? Bosch I hear is shity so whats the other one Denso?

if you guys can think of anything else to check out that would help me out a lot, Im broke and going crazy! thanks

 

all fixed, it was the regulator on the rail.... what a difference