[mastersat1]

How do i find internal vacuum leak? I have 14-15" of vacuum with a shaky needle. Motor has 135-140# compression on all cylinders. This motor is a replacement long block with salvage block. I had to use old intake in order to use tbi instead of cpi that came on salvage block. I replaced head gaskets while engine was out. Motor is running rich and my understanding is that low vacuum will cause high voltage on map sensor which will trigger it to run rich. Map voltage is high, 4.5v at idle. Can't find any external leaks. I sprayed a little starting fluid in the valve covers to see if guides were leaking and that didn't change the idle. Has new egr valve and solenoid. Have plugged all ports to check amount of vacuum from motor. I ran a little hotter plug in it and the problem was not as dramatic. Will hotter plugs increase the vacuum? Or am I just compensating and burning the extra fuel. I don't know year of the block for correct plugs. Need to know how to isolate the vacuum leak. Would greatly appreciate any help.