My 03 yukon has had alot of work done lately. I started fixing everythng when gf brought it hme with check engine light on. When I drive truck it runs good but at a complete stop it has a slight miss. I have changed plugs, wires, o2 sensor, catalytic con, changed oil, motor flush, gas treatments, cleaned mass air flo sensor, good compression, good fuel pressure, intake cleaned, all coil packs are good. The truck keeps showing multiple misfire on computer. I am burning extra gas
Can bad fuel injectors or fuel pressure reg. make truck idle a little off, but be fine after take off?
i would look at the freeze frame date that is stored in the cpu with that pO300, that will give you a direction to go into. fuel pressure variance can trigger a misfire in extreme situations but i do not think that you are in that situation. a misfire can be caused by many things. that code only picks up in a weak power stroke for what ever reason.
Can bad fuel injectors or fuel pressure reg. make truck idle a little off, but be fine after take off?
sounds like bad wires or fowled plugs
Try a fuel injection service / cleaning before you start tearing the engine apart to do injectors. I've found a good service cleaning fixes most rough idles and minor misfires
Did you get the codes read, since you stated the check engine light was on? So, basically your wasting money till you get the problem diagnosed first.
Multiple misfires could mean the crank sensor may be screwed up somehow too.
