[jonnyboy9012]

Hey... i had the same problem when i turboed my PT (with a motor similar to the 420a... it is acutally a sub-division of that motor called the "EDZ"). The problem did turn out to be the turbo.I couldnt figure the damn thing out, i checked all the crankcase lines, compression checked... basically everything i could think of. I turned out to be the turbo seals on the inside, i bought a cheap ebay turbo (i know... i know, but i already got what is deserved and i was broke at the time) that lasted great for about 2 weeks, the outside of the turbo itself was of excellent quality but where the saved money was on the bearing housing, the seals where shot and it would blow oil. It blew oil because the seals had worn to allow tollerances to fall out of spec... i dont know how many thousands of an inch are supposed to be between the journal bearing and the shaft, but i know mine was enough to cause blowby. I still dont have an explination on why it did it when i lifted on the throttle, but it did... and the seals where the culprit. Hope this helps.