Dump pipes and fouled plugs 2g 4g63t

I just dumped a 1996 2g 4g63t into my ‘87 mighty max. I’m trying to get the truck to the muffler shop to get the exhaust installed.
I have an 18” piece of 2 1/2” pipe as a dump from the turbo. The o2 sensor is roughly 10” from the end of the pipe. The factory turbo waste gate has a 10” pipe dumping into the atmosphere.
Like I said I am just trying to get it to the exhaust place but the plugs foul right out. Number 3 and 4 foul first. Could the exhaust dump issue be enough to make the ECU think it’s running lean and overcompensating and fouling the plugs?
I’m planning a full diagnostic after the exhaust is installed but I am just trying to get it there. Will the full exhaust that much difference and should I just tow the truck to get the exhaust installed before diagnosing? Thanks in advance GTP

ive had this happen on a 1g motor.. it ended up being the temp sensor on the t-stat housing.. when it goes bad.. or has a bad connection.. it reads -40 degrees temp and richens the hell out of the system which fouls plugs in like 10 sec... make sure the wires and plug are connected good.. if they are then try replacing it... number 5 in this pic..http://www.mightyram50.net/vbulletin...id=27755&stc=1

my bad.. #3 is correct one