1999 Sl 1.9 lt multi misfire

[willm]

I had code po400 and checked and cleaned EGR vlv, EGR vlv was replaced before I bought this 6 months ago, has always had high idle 11-1200 rpm. Cleared code but would come back in a few days. All of a sudden started bucking and jerking, now code po300. Removed throttle body and cleaned and replaced IAS, runs ok high on idle cold still, once warmed up bucking and jerking,po300 come up. Has new NGK plugs and napa wires. Any help would be awsome.

[Banjoman]

Look around with the search feature for P0300 issues, there's a lot to find.
A bad coil, or maybe just cleaning the coil terminals and grounds. It may also be a vacuum leak with the high idle. If the coil terminals have corrosion on them, use a green scratch pad and clean them off.