94redtransam

I just scanned all my sensors. My manual says MAP voltage should be around 1.5 V idling and climb to 4.5 V WOT. My MAP is 1.5 idling and then varies from .8 to 1.8 V when I go up to WOT. Does that mean I have a leak somewhere? I don't know much about these things but Im trying to learn. My car stumbles and occasionally backfires when its warming up for the first 5 minutes. Also, the EGR% was constantly at 0% at idle and up to WOT. Is that supposed to change? THanks for any help.