Expert: Robert Summers - 3/14/2008

Question
Hello, I have a 95 Chevy suburban that hesitates or stumbles when I accelerate or when i mash on the throttle durring driving speed.  I replaced the plugs, wires, cap, and rotar.  I replaced the fuel filter, and i have good fuel pressure.  I think it is the coolant temp sensor because when i unplug the clip from the sensor it runs great but it will not start when it is cold.  I replaces the temp sensor and it did not change anything.  I unpluged the ECM to reset the codes but it did not help anything.  I am getting desperate.  Please Help. What could be wrong?

Answer
Hi Mike... can you get a scan tool...read the codes... from your discription it sounds like it could be a bad coil...also try some inj cleaner..could be one is plugged up...it could be the temp sensor but if you replaced it and nothing changed i would suspect something else...check vacum lines for a leak as well as a possable leak around the intake...also try cleaning the idle air control...use a good air intake cleaner... hope this helps