These usually set a code when the knock sensor goes bad.

 

Ya could be... some times they work some times they don't if you can wait til next week maybe I can send you a loaner with the antitheft turned off.

 

Who can turn the antitheft off?

 

I can do it but I dont have any more licenses on my efi live software. I have a 2000 silverado with 5.3 and a spare pcm or 2

 

I have a couple more questions for you.

1. Did this truck have any codes when you first got it???

2. You said you deleted the cats and the rear 02 sensors. Who adjusted your computer for that???

3. Did you check all the other things like Spark plugs, spark plug wires, connections, compression, vacum leaks, and so on???

4. Have you tried any fuel injection cleaner, and did you clean the throttle body yet???

5. Are the mass air flow sensor readings on the truck the same as the camaro or does it apear that it is functioning the same?

6. I know the problem is occuring while driving under load but can you duplicate the problem with the truck in park by reving the engine???

7. Specifically what type of scan tool are you using to read the Live data???

 

It had one evap code, and some rear 02 sensor codes. Since the delete of the rear 02s and cats, no computer adjustment has occured. I planned in doing that in the future with a handheld programmer to disable the associated trouble codes. I have checked plugs and wires, which both arebin great shape, plugs are brand new looking but Ive just looked at them, not chnged any. They look like brand new ngk tr5s. I have not done compression check. I have not put a vacuum gauge on yet either, but I have sprayed the intake and tb area with water while running looking for any vacuum leak in that area. I have not tried fuel injection cleaner yet, nor have I cleaned the tb yet. I can do tomorrow if you think I should. The mass air readings are close to what they read on my camaro, not much difference there. The only thing that can be duplicated in park is the momentary dip in ignition timing with the throttle blip. It is audible, but not apparent unless your watching the timing closely. However, the small dip does create a small stumble, or just very poor throttle response. This is the only thing I can re-create in park. I did notice something interesting tonight with the timing again where the timing seems to be very unstable while cruising at a steady rpm and speed, but I want to pull the same scenario with my camaro and see what it does first before I go down that road. The tools in using are kind of a mixture between my predator for my car which does live data, and my buddies Matco handheld scanner, which does live data too, but its faster and graphs everything, so its easier to see small fast changes. That's how I seen the ignition retard. I notice it with the predator, but the matco paints a better picture as I can see it much more clearly.

 

Did you check the gap on the plugs by any chance??? Originall spec was .060 GM later changed it to .040 with the original platinums or irridium or what ever they are.

Does either scanner show live miss fire data???

 

The o2 censors point to a lean condition. throttle % 50 or above = low o2 censor mv. no fault codes. I would try to check the fuel pump under a load, check the spark plugs, check the plug wires. Instead of just throwing parts at the problem. Does the truck backfire and buck?

 

I did check the gap on the plugs. They were sitting at about .065 as if someone had set them to 60 and they had grown, so I put them all back down to 60. I had no idea they changed it to .040. Ill have to do that tomorrow after work.

Neither scanner shows any misfire.

 

I checked the plugs and wires. The plugs looked clean enough to eat off of and were close to oem spec gap, so I put them back in at .060. Plug wires all tested excellent but I broke one pulling them off of course, so I replaced them all with a set off my camaro as I put new taylors on it at the same time. I did check the resistance in all the wires before putting them back on.