I got my engine back together and on the second road test I found the exact same aggravating problem as before!
Engine starts right up an idles at 1100(high but perfect)
Warms up and around 1/4 mark runs great
1/4 - 1/2 seems to have only slight stumble on accel. if you baby it
Ok, heres the problem...at this point with the engine around 1/2 heat on the guage,
the idle surges from 1100 down to 800 then back up to 1100.
This happens persistantly at one second intervals.
It does not effect drivability or happen when laying on the gas. Only at idle. Sometimes it will not happen with the ac on but if the heat goes up even more it starts. I have searched many times both before and after the rebuild and am still stumped
.
Ps. When I remove the vacuum hose from the fuel pressure reg the surge is quicker, maybe twice per second.
Help.