running away

2000 xj, 4.0, command trac, a/t, 89640 mi:
after much research and no hard resolution to my oil pressure problem (or lack thereof; 10 psi @ 2500 rpm), i got a reman long block.. book time for the swap is 14 hours, and i did it in about that.. the swap was easy but then again my shop is well equiped..
however a new problem presents itself..

after topping off the fluids, and priming the oil pump (60 psi off the starter).. when i went for the money shot, and cranked it over.. when it started the motor wanted to run away, that is, it wants to rev up to its limit..

i checked the throttle linkage, cruise linkage and the a/t kick down cable, the throttle plate is closed. i checked and rechecked the manifold bolts and torque, and all the vacuum lines, all ok. The iac is stepping just as it should be.. ( i hadnt disassembled it till this problem came about..) in fact other than brackets, mounts and manifolds nothing was disturbed..

awhile back i had a wrangler with a 4.0 come in with a similar problem with an erratic idle, and when you opened the throuttle for a sec, the motor wanted to red line, so naturally you had to shut it down.. turned out to be a bad intake manifold gasket and after the new one, it was just fine.. but like i said, i checked and rechecked and re-re checked the manifold bolts and gasket and its all spec..

any thinkers out there?

Brake booster vacuum line?

all the vacuum lines are in tact.. tried an experiment this morning.. with a hand over the throttle assembly to seal it off i cranked it over and still did the same thing.. so i got a felpro manifold gasket for it today to replace the victor gasket that came with the long block.. ill swap them tomorrow am

well i see i only had one other person check this thread out, but ill give you the results anyway..
after removing the intake manifold, i had a better view around the exhaust manifold.. there was visible seepage around the 4,5 and 6 cyl exhaust ports (assembly oil and unspent fuel). after i installed the felpro manifold gasket and reinstalled the manifold and p/s pump, fan, etc.. and fired it up, i had one of those adrenaline rushes that you can taste in your teeth.. runs beautifully. so i ran it through the break in procedures that i got off of all data, checked for leaks, topped of fluids and put its first fifty miles on it.. couldnt ask for anything better..

incidentally, if anyone wants to know where i got my long block ( since the two local engine shops here gave me a time frame of a month or two, maybe..) promar.com i was suprised to find they had my head/block combo in stock (449 block, 331 head) $1900, no core charge and free shipping.. beat the hell out of the two local builders (one wanted $2500 to rebore, hone and balance and the other shop wanted about $2300)

anyway, it all worked out

Dude, 80 people checked out your thread. We could tell that you had things well in hand. We appreciate the update. Did the gaskets look different when you got them? Was one thicker or a different material?

well the victor gasket is like two pieces of tin foild sandwiched together, while the felpro was more like a credit card.. the felpro has a teflon-like coating on both sides.. internally however the felpro has the same gaps between intake and exhaust ports for the expansion difference between the aluminum intake and cast iron exhaust manifolds