Question about using a timing light on a 88 model

[2shus]

Here is a little history first. I bought this truck (1988 D-150 318 TBI) a while back and it never has had quite the power I thought it should. Also it would die frequently. I let the parts store hook up a code reader and it would not recognize the computer. The computer was brand new when I bought the truck and it looked like a new one. So I began to nose around with it trying to find problems. First I found no vacum to the EGR valve. Found out all the ports on the throttle body were plugged up with carbon and not allowing the pcv valve to work. This also did not allow several other vacuum items to function so I pulled the throttle body and cleaned it all up. Then I used mopar combustion chamber cleaner in the truck as per instructed. Then I decided to hook up a timing light and check the timing and found it was way off. In fact I could not even see the mark on the crank pulley at all until I began to adjust the distributor and then it started to come into sight. The catalyst sticker calls for 10 degrees before TDC so I set it their and it ran like crap!!! The only way I can get it to run halfway decent is to set the timing by ear and when I do then once again the mark is completely out of site and the scale can not even be seen. It does run a little better their but pings. Also my tranny shifts hard and late. I gave it a full tune up and oil change after the mopar combustion chamber cleaner and replaced the EGR valve. I also unhooked the battery and let it set overnight in case the changes would somehow affect the computer. This is a 1988 Dodge D-150 4X4 with a 318 TBI and 108,000 miles and I am told was the first year that computers were used on the trucks. Does the computer truly control timing on these like the newer ones ? My haynes manual does not say anything out of the ordinary about timing this truck. I know their can be some allowance for wear on the timing with an engine that has 108,000 miles but their should not be that much. Do the 88 models with computers still need the timing set with a light or have I really missed something? I am getting ready to go out and pull the #1 plug and run it TDC and see if the distributor is in line with the #1 plug. Could it have jumped time? I have driven it to work every day for a month or more! I would appreciate any replies, thanks.