ok guys i have a 98 Bonneville 3800 n/a. im having a couple issues i think are related. the car idles very high 1500-2200 rpms until the thermostat opens then runs normally around 800rpms. in addition to that sometimes when the therm opens (closed loop i think) the engine starts stuttering and missing and sometimes dies, then you can fire it up and it runs perfectly other times it dies with no warning and then you can start it back up and runs perfectly. it threw a PO306 cylinder 6 misfire and PO101 Maf i have gotten a o2 sensor fault with the others but not every time. the maf tps iac have all been changed recently. any help would be greatly appreciated! very desperate here thank you!