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Advice w/ C4 Problems

A&Mbronco

Sr. Member
Joined
Nov 18, 2004
Messages
547
Loc.
Houston,TX
Well I had my c4 rebuilt just over a year ago and its giving me problems now. Problem is when it shifts between 2nd and 3rd gear it will jump back and forth between the two until I rev it high enough to stay in 3rd (about 4000rpm) then it will run like normal. Anyone have any suggestions because I'm no expert on auto trannys and I dont think the shop that rebuilt the thing knows too much either...
thanks
 

BwoncoHowie

C-4 Wizard
Joined
Nov 11, 2002
Messages
3,571
Check for cracks in your vaccuum line/hoses going from your intake manifold to the modulator. Put a vaccuum gauge on the modulator line if necessary and test the vaccuum signal at the feed line that plugs into the modulator. 15-18 in.Hg is needed.
 
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