compression on a 1999 mazda 626 2.5l and sensor?

[Jess?c??]

I just did compression test on my car cylinder 3 was giving a misfire so i checked every cylinder every cylinder had a little over 180 psi cylinder 3 had like 145-150 isnt that still enough to run fine though,also if anyone cN TELL ME WHAT THIS SENSOR IS THEY AUTOMATICLLY GET BEST ANSWER. its located on the top of the air filter housing it is a two wire plug and 1 line goes to the fuel pressure regualotr one goes into the intake i went to mazda and the parts guy couldnt figure out what it was, and could that sensore cause a misfire on 3/ i got new plugs and wires also