87 BII rpm problems when warm

[ujawa69]

ok on start up engine runs accelerates and revs as it should. after it reaches operation temperature it wont reach 5k rpm and with a load at operating temp it wont run over 3k rpm. it gets lower as i drive. if i kill the engine while the clutch is in and pop it to restart it it runs better for a short while. gets from a-b but barely. have replaced both fuel pumps and filters have checked and double checked all the vacuum lines have around 35psi at the pressure regulator. only thing in the fuel system i havent checked is the injectors. was wondering if anyone has any input or ideas as to what the problem could be. thanks much.

[drofman]

Plugged exhaust?

[ujawa69]

not plugged. tried changing out the distributor components and timing it. still no luck. has no cat and has lots of exhaust flow. only thing i can think of at this point is a vacuum problem.

[AlaskaBronco]

Replacing the ECT sensor worked for me.

http://www.broncoii4x4.com/forum/viewto ... f=1&t=3884