99 Sierra 5.3 "bogging" down only at full throttle....HELP!!

[vintagephilg]

I have a 1999 GMC Siera 1500 extra cab, with the 5.3 V-8. It bogs or hesitates (almost like not getting gas??) when you give it med.-to full throttle...but runs great at small to partial throttle openings, if you accelerate relatvelly slowlly (I was doing 70-80 on the highway no problem....) its runs fine?? I just changed the oil and installed a brand new AC Deco Fuel Filter (it looked very old and the gas that came out of looked really dirty/nasty..) and I even ran a bottle of Chevron Techron fuel injector cleaner in it... Any clue to what the problem might be or what I can do to fix it?? Please help...

Phil

 

[97SierraGuy]

Phil,

I am having the same problem in my 97. It started while I was towing my boat last weekend and I have had this same problem ever since. My check engine soon light came on while towing but has since gone away but the problem still remains. I had my pvc valve replaced one week before this happened. Could the new pvc be the problem?

Does anyone actually reply in these forums? There are like 200 threads in here with no replys.

Thanks, Doug

 

[97SierraGuy]

Fixed it

It turned out to be the oxygen sensors. There are 4 on my truck. 2 on each exhaust pipe. One before the Catalytic and one after. I replaced the 2 before the Cat and now everything is back to normal.

Hope this helps somebody, Doug