Hi I am having a new problem with KR that wasn't there previously. I tuned the vehicle after doing a mild camshaft, Shorty Headers and K&N cold air intake. I had done the Maf and the Ve tables all with a wideband and checked with narrows afterwards, I then changed over the base spark map to the same one as my GF truck which had been dyno tuned with similar mods. I scanned for knock around 10 times on different terrian, hills, steady driving and WOT pulls; never coming up with any KR so left table as was. This was all done a little over a year ago.
Now recently I have been having a hesitation around the 1900-2100 RPM area so I decided to do a scan and see if anything was going on. From the scan I could see that there was a couple of degrees KR in that region and on a 3rd gear WOT pull but not in 2nd. The KR in the 1900-2100 region only seems to knock when going up hill or under load, which is in the 75 up map area. I also noticed that the injector ms on each bank would be different of 1 ms or more at times but the narrowbands would be reading about the same amount of fuel. So I started with returning the timing table back to stock which pulled 2 degrees timing out of the cruise areas. Still had knock there so pulled more timing in that area and was still getting knock. I went over the maf and VE tables again with the wideband and everything was reading within a couple of percent. Checked the fuel pressure and it is reading good.
I am not sure where to look next or what to try and any help would be very appreciated. I am thinking it may be the injectors as they are stock with 315000km on them. I would try testing them but it is the spider assembly with poppets.
Sorry it reads like a story was trying to cover as much as possible.
Truck is a 99 Jimmy with 4.3 and 4l60e recent mods are the camshaft, headers, cold air intake, spark plug wires, cap & rotor, underdrive pulleys, Transgo shift kit and 4.10 gears with 29 inch tall tire.
Here is a couple recent scans, the speedo tune was the one i have been running for the past year and the spark one is the one I am currently running.
So my problem turned out to be a bad ignition coil wire. I didn't suspect a bad wire as they all looked good. Didn't notice the problem until it was dark out. Replaced it and all the kr went away. Gained back power that was missing. I guess it was misfiring and causing the kr count.
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