could my engine run like crap and wont go over 2000-3000 RPM if i would install an older engine with one of this timing sprocket with abunch off round holes diffrent than the original in my 2006 5.3... looks similar to this one but not the same and i know it dosent have all this holes on it more like a 1 piece round plate? well after i installed an older engine on my 2006 silverado with the cam sprocket im talking about it stating to do this things... once i turn the engine on it will rev. easily over 5k-6k RPM and once i let it idle and try to rev it again it wont even go past 3k RPM or 2k RPM's it sucks and with the peddle all the way down. it wont trow any codes checked that... & also i checked and swaped the coils, map, throttle body, crank sensor, wires, plugs, knock sensors, everything i can think off... fuel pressure steady at 55psi.... any one could it be this or the tune?


my original sprocket looks more like this...


new sprocket installed in the 2006 computer but old engine with EGR- dont know correct year on engine.

 

If the original motor had the top cam sprocket and you installed the lower pictured sproket, then your not getting the cam position signal to the pcm. Do you have a cam sensor connection on the timing chain cover of the original motor?

 

I was under the impression that the PCM only uses the cam position signal for cranking, so if that was the case you might have a problem starting the engine, but once it's up and running it should be OK...plus, I thought that the 06 is a GENIII which should have the cam sensor at the back of the camshaft.

 

my engine has the cam sensor on the back and my engine fires right up quik with no problems. it only when it starts to idle as soon as i turn it on it dose this thing... only reving till 2-3k rpm. i will make a vid. tommorow and post it up so you all can see what im talking about.

 

It sounds like your truck is going into "limp mode"
My truck did the same thing when I ported my TB.
All I had to do was unhook the neg from my battery and let it sit for about an hour and hooked it back up and all was good.
Are you using the pcm from the 03 or the 06?

 

2006 my truck is 2006... im thinking is doing sumthing like that cause i can hear the idle sound change when it starts doing this. but no codes - its freaky.

 

Can you verify the throttle position switch is operating? like with efilive, hptuners, or a scan tool.

 

yup its opening... and the original cam sprocket on my 2006 5.3 is like the one on top but with 1 half circle lobe thing no exactly like the ls7 sprocket im thinking it will be that or the tune i havent checked it.

 

I don't see how the cam sprocket could be giving you a problem, especially an intermittent one that you have to let idle to happen first. I haven't heard of the sprockets being keyed or marked any differently through the years. Have you double and triple checked all of the grounds, anything that could have been missed? Melted wires to the TPS, or junk on the MAF sensor. Are the O2 sensors switching back and forth rapidly as they should?