96 GMC Sierra, just started doing this afew days ago. truck just starts rolling when i put her in gear. idles normal, not racing at all when i start her. truck won't slow down as normal when i let off the gas. just keeps going for afew seconds, then slows down. also this speed seems to make the shift gear kick abit. any suggestions what this sudden speed difference would be. tks for any advice...daveywonder 6 cinlinder, 1500 full size, 96 yr. WAS TOLD THAT A AIR CONTROL WAS THE PROBLEM...any truth to that, and how would i fix that??? friend told me this. YES, I DID CHECK THAT NOTHING WAS OBSTRUCKING THE GAS PETAL..........................GOOD DAY

 

I'd start by making sure the throttle is not sticking. That's a cable accelerator right? It could be sticking on the engine end, not the petal end.