Expert: Robert Summers - 1/2/2008

Question
Robert. Recently while driving my truck it started bucking and hesitating. It only happens at part throttle cruising at a constant speed. I found the EGR valve is opening just off idle in neutral causing this problem. When I unplug the EGR control solenoid, the EGR closes and the engine runs fine. I have replaced the TPS and the EGR solenoid and still have the same problem. Also, the engine must have some tempurature (120-130?), before problem starts.

Answer
Hi Terry... does the egr now open and close when it's supposed to....try removing the egr and cleaning it...could be not closing all the way when it starts to come to temp.also check that temp sending unit is reading properly...could be egr opining too early if reading temp wrong...hope this helps