RX7 allnight

ok bought this GTU cheap had bad coolant seal, did the temp fix using block weld thanks to rotaryresurrection.com's write up..before i did the temp fix the car started great everytime...did the temp fix starts great runs good(as good as it should being midly clogged cats) ok no water in the oil..but now it has trouble starting.... theres no pattern some days it will start right up drive it around town shut it off get gas start right back up again, goto a friends house for 30 mins to an hour, get back in starts back up let it sat for 5-6 hours didnt start up...next day wont start, than it starts fine the other...messed with the tps...it didnt read 1.0ohms till the screw thing was almost all the way tight...so something wronsg there...next day after that it starts, but when driving it bucks because of TPS set wrong so i let it sit try to start nothing, after that next day it starts now it just wont...it starts and ran good before and after the TPS adjuments so thats not really it i think...its starting to get annoying because there is NO patterns in the start weather it be cold warm...i disconnected (the tps) a few times and tried things but that didnt have any affect i did the poor mans comp check and all pusles sounds strong and even...any advice things to check/look for would be very helpfull thanks