1999 Mercruiser 5.7 TBI hesitates but does open up

ThaBiggT

Recruit
Joined
Mar 1, 2018
Messages
4
The engine runs strong at wot, but when accelerating from idle it will bog down before coming back to life and running great. It you accelerate slowly it will act fine. Fuel pattern and flow from the injectors seems strong and constant. Plugs, wires, cap, rotor and coil are all new. I timed it myself by jumping the a&b on the dtc. Great running boat. Just the hesitation when getting on the throttle quick. Thanks for the help.
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
42,630
Start by checking fuel pressure 30 psi at 1800 RPM

Turn key ON and measure voltage at TPS to see if it smoothly changes value as the TB is opened
 
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