Backfiring 99 Chevy suburban
I changed cap rotor crankshaft
sensor an map sensor truck starts
an runs but is backfiring an won't
go over 30 an only codes left are
egr valve an mass air flow sensor
Your problem could be just the MAF/MAP sensor. After you correct this, along with the EGR problem, if the problems continue, you might have an exhaust restriction, like a clogged catalytic converter. The backfires could be a timing issue. It might be that the car has put itself into limp/safety mode.