I have a 2000 chevy half ton and it has a serious crusin problem when i am driving down the high way when i hit about 65 in drive and about 2200 rpm it starts chugging sommthin firce almost like a tranny slip but once i hit about 70 and 2500 rpm runs like a champ. Also when i start it up it idles pretty rough or when i stop at a stop light i'm stumped guys. took it to the chevy garge they told me my evap can was plug next to the fuel tank. changed it and well same story
It almost sounds like a MAFP might be going bad. They sell cleaner it Pep Boys. It could also be an O2 sensor. It is strange, but do any warning lights go off? Lastly the lock-up on the tourque converter might no be engaging properly.
there are no warning lights its weird ha ha i wish somthing would just break so i could find out what the heck it is
