99 7.3 runs intermittently bad

[4x4 Nut]

Hello, we have an early '99 7.3L truck with 133,000 miles that has an intermittent miss. No engine light and no codes (using a simple code reader tool). One day last winter it ran poorly and some frozen water was found in the bottom of the fuel bowl. That was cleaned out and a new filter put in. It ran fine for a number of months and then started to miss with loss of power of course. Some days it will run fine, other days it's just slight, and still others are very bad. The fuel tank has been dropped out and is very clean inside. The fuel pump has been replaced.

Sometimes a cold start will be fine and other times it misses and starts a little hard. When it misses it will smoke a little, but clears up quickly and runs with just a very slight miss. Usually it will clear up nicely in just a couple minutes and drive fine. As it warms up though it will start to miss and loose power- don't notice any smoke though other than at start up.

About a month ago I used an infrared thermometer on the exhaust and found the manifold was cooler on #1 and 3 exhaust ports. I also checked connections on the injector wiring at that time and installed clips on the under valve cover harness. That seemed to take care of it. It ran great up until about a week ago and then started up again. It hasn't been a consistent thing, although it seems like it is now because it's been acting up every time recently.

Yesterday I fired it up to check it out. It started hard and ran bad (dying once). I let it warm up for about 10 minutes and then took it down the road. It had a single miss, but quickly started dropping more. Within 1/2 mile it was so bad it would only pull the truck at about 10 MPH and shortly after it died. It's like I was turning injectors off 1 by 1 with some fading back in once or twice (kind of like a cough/ chug if you were to run a truck out of gas). Trying to restart would get some fire, but not enough to run. We pulled it back to the shop where it fired up again (about 10 minutes after dying) and ran with a miss. (I'd say probably 2 cylinders down).

Today I pulled the valve covers and fired it up. It had a definite miss at cold start but better than yesterday. While running I unplugged injectors and both 1 and 3 didn't make a change. The others you could tell would drop off when unplugged. After a few minutes it was running with just a slight miss. #3 would drop off when unplugged and #1 would act like it was about 1/2. You could tell a slight change, but not as much as unplugging another injector. I've checked continuity on the under cover harness and the gasket and all seems fine.

I'd suspect maybe a couple of injectors, but what has me puzzled is how it will drop off more than just 2. The oil has been changed and was just done so recently. Would anyone have a suggestion or thought? I don't have a tool to buzz or check contribution, but have been considering getting the Auto Enginuity one. Any suggestions without that right now?

Thanks guys.