Well yesterday i decide to try the seafoam through the brake booster. But, when i went to start it up to flush that stuff out, it was obviously hard to start, but it backfired and smoke came out from under the engine cover. i got it to start and it ran like crap. I took it for a drive on the highway it runs fine when the throttle is on but it doesn't when its idling. plus it's throwing a code of p0171 which is a lean mixture. when its warmed up it idles all messed and when its cold, it has a hard time find a idle and jumps in between stalling and 3000 rpms. what could be wrong? i'm goin out today and checking for vacuum leaks, anyone else have a idea???
