I have a 2002 7.3L with a little over 140,000 miles on it. I had no problems with the truck until I hit 135,000 then I found fuel in the radiator. I replaced the injector cups and injector o-rings and fixed that problem. Then I started getting a p1211 code when I would get on it to pass someone. I ended up replacing the HPOP to fix that. Now I'm having this weird idle where it changes randomly. It only changes by around 200 rpm's then it returns to normal. Low end seems to be a little sluggish too and the problem gets better as the engine warms up. Runs fine at highway speeds. I have the AE software and it's failing cylinders 3 and 8 on the cylinder contribution test. Research tells me that number 8 usually fails due to it being a different injector. Could #3 be causing my idle problem? That leads to another question. Do I just swap 3 out with a different injector and see if problem follows or do I need to run a compression test? I don't notice a "miss" when it's idling. The rpm's rise then return to normal. It has a new ICP regulator and ICP sensor. I also installed new injector wiring harnesses when I replaced the injector cups. Thanks.