Here is the diagnostic for intermittent "Hesitation". Do not skip a line.
HESITATION, SAG OR STUMBLE
Momentary lack of response when accelerator is pushed down. Condition occurs at all vehicle speeds or usually occurs when taking off from a stop. If severe enough, may cause engine to stall.
Possible Cause & Correction
Check the following items:
Visually check vacuum hoses for splits, kinks and proper connections as shown on vehicle emission control information label.
Check ignition wires for cracking, hardness and proper connections at both distributor cap and
Check wires for pinches, cuts and proper connections.
Check fuel pressure.
Check for poor quality or water contaminated fuel.
Check for fouled spark plugs.
Ensure the installed PROM and/or PCM is correct for that particular vehicle. Check with dealer for latest application information.
Check for a binding or sticking TP sensor. Voltage should increase steadily as throttle is moved toward Wide Open Throttle (WOT).
Ensure PCM-controlled idle speed is correct.
Check EGR operation.
Check engine cooling system thermostat for proper operation and heat range.
Check ignition control system ground circuit.
Check canister purge system for proper operation.
Check charging system output. Repair charging system if voltage is less than 9 volts or more than
Check fuel injectors. Perform injector balance test.
Check injector harness locations. Ensure injectors are connected to correct injector/cylinder according to firing order.
Check heated oxygen sensor ground (corroded threads in exhaust manifold or pipe).
Check for air leaks between MAF sensor and throttle body.
Check air induction system for restrictions.
Check for intake valve deposits.
Check MAP or MAF sensor.
Check distributor vent system (if equipped).
Tuesday, February 24th, 2009 AT 6:48 PM