Off and on code 45 (tps) and 51 (egr) problem. Tried a new tps, didn't make a difference. Took it to a friends shop (no charge) to check the tps, they said they just plugged in the idle circuit but now the egr code was flashing. I checked to see if it was stuck by physically moving the diagram and the dash light turned off, good to go. It lasted 20 min. Checked vacuum and don't seem to have vacuum from the bottom of the throttle body (can I use the vacuum from the intake runner?) Now both codes 45 and 51 flash randomly, last week had 2 days driving (in the snow) with no issues, but it's back. This is my bush buggy so its at the bottom of the budget. Has anyone else experienced this? Checked connections a few times no change. Should I replace the throttle body or the computer? Carburate? Top of my list is propane. 

The EGR code is probably because of restriced EGR passages.  The EGR system needs to be disassembled and cleaned out (including the EGR valve).  EGR passages clogs and restrictions are very common in trackicks.
The TPS may just need to be adjusted correctly.  If that doesn't fix the issue and/or if the TPS specs don't check out, then the TPS is likely bad and needs replaced.
I noticed you said you replaced the TPS.....was the replacement a known good one?.....was it adjusted correctly?  There are some pretty precise adjustments that have to be made to the TPS, for it to work correctly.

Thanks, I'll pull the EGR and give it a clean. As for the TPS I installed a new one according to the specs and no difference. Sometimes its fine for a couple days, somtimes it good for 20 min. Very random.

You have to clean the EGR passages in the head and intake too.

Are you talking pulling the intake? or can I run a wire down the passage like a pipe cleaner?

You can probably do a good enough job by running a wire down it (a broken speedo cable would work pretty good, if you happen to have one).  Just run it all the way down the passage several times and use some brake cleaner and compressed air to further get the buildup out.