i was headed to the track friday and was runnin like 100 for 5 min. and 145mph for like 15 secs and when i slowed down car started running like poo under 2500 rpms but clears up over that and seems to run fine . i pulled rear leading plug at track and no change in idle replaced both leading plugs with bur9eq's and same problem so im thinking clogged injector or vac leak or leading ignitor going bad .

any help appreciated thanks in anvance