Quote Originally Posted by 34_40 View Post
Do you have a vacuum gauge? Reason I ask is you should measure vacuum from a cold engine untils it dies. If you're losing vacuum when it get to operating temp. that''ll eliminate the ignition and fuel systems. I've had a couple cars with dual wall pipe that had the inner wall "swell" and block off the exhaust system. They would run good cold then slowly lose rpm \ power. We could only diagnose this with a vacuum gauge. I've seen a car do it with a blocked cat. converter too. Act like a bad fuel filter or weak coil but the darn thing just couldn't breathe! It's easy to check too!
Yes that thought did occur to me, such as manifold possibly heating up and opening a gap in the sealing surface as to induce a major vacum leak. I guess I could pull gauge off my vac brake bleader. I was going to try dist from my 66 but was too hot this afternoon and I just didnt feel like sitting on that hot engine. It does seam sometimes I end up with somthing like that, it cant be the simple fix, has to be the bizzare one. Just my luck. But I thank you, never thought to check the vac. For another reason I was going to install a direct mount vac gauge, just havent gotten around to ordering one yet. But I may do that before I jerk out that other dist.