Could be a failing fuel pump that isn't giving enough fuel pressure to supply the engine under loads. You can check this with a pressure gauge.
Fuel pressure should be 55-62 psi and hold steady. (No more than 5psi drop) Check regulator by running engine and pulling vacuum hose. Pressure should increase. If not, bad FPR. Also check for presence of fuel in line. Any, bad FPR
Tuesday, February 22nd, 2011 AT 3:03 PM