What is most likely cause of surge/bucking when spedometor fluctuates in a 2003 Rendezvous?

Question

Diagnostic codes: PO102, 134, 135, 300, 440, 442. Symptoms are worse in hot weather and seem to go away as it becomes cooler. The engine surges/bucking, but only when the spedometer fluctuates from actual speed to 0 and then goes up and down until finally ending up on the actual speed at which time the surging/bucking stops. Check engine light is on. What is the most likely cause?

Answer 1

P0134 Oxygen sensor circuit no activity detected Bank 1 sensor 1

P0135 Oxygen sensor heater circuit malfunction Bank 1 sensor 1

P0300 Random misfire

P0440 Evaporative emission control system malfunction

P0442 Evaporative emission control system leak detected small

P0102 MAF (mass airflow) circuit low input

Random misfire is more than the likely cause, this can be from the CKP sensor (24X) which is located at the front main pulley, When this sensor does not give its signal it will cause the surging and bucking, Whe the engine surges and bucks it set off a MAF code which is the result of the engine condition ,  As for the evaporative emission leak check the fuel cap and replace if the seals of the fuel cap shows any tears,As for the oxygen sensor  with no heater activity check the engine fuse box fuse listed as 02 sensor fuse 10 which is a 15 amp fuse, Power and ground of the 02 sensor needs to be check, if there is no power or sensor signal the ECM is at fault.

Answer 2

Many things can cause those problem and there are too many codes. You should start by erasing all the codes and start working with the first code that comes back. From what you describe you could have a problem with the Mass Air Flow (MAF) sensor, the other codes are for the EVAP system and O2 sensor, which usually won't cause an engine performance problem.

P0102 Buick - Mass or Volume Air Flow Circuit Low Input

Read more: https://www.autocodes.com/p0102_buick.html