Temperature problem with 454mpi
 

Hey guys, I have a 1998 baja boss 302. I just had a problem with high fuel pressure and sovled that.
I just took it out for a ride and the port side motor seemed to be running hot.. It was a little over 180. The other engine was running at around 120. I noticed that it would go up and down to indicate that the theromstat was working. When it went a little over 180 I had it pop throgh the exhaust on two different times. I shut the engine off and let it sit for around 10 min and it went away.
When I got home i noticed the port side has a thermostat and the other engine didnt. I took the thermo out of the engine and let it run with the hose hooked up and it never went over 100 degrees and no problems with it backfireing out of the exhaust.
Two question, Do you think I could of had fouled plugs from over 85psi of fuel pressure???? Or was it from running hot. The engine runns and sounds great, so I think I can eliminate a bent valve or something since it comes and goes...
Also do I need a thermostat for a fuel injected 454mpi???? Is it running to cold with out one.. Maybe to rich??

Theyt should run 160-170* on the gauge when they are warmed up.

Yes, you need to run a thermostat on a 7.4MPI.

any other help??????