GMC Repair: Engine Surges 50-60 mph, air induction system, intermittent faults

Question
2000 GMC Jimmy w/4.3 v6 4wd & auto trans, 85000 miles w/no maintenance.  Engine surges between 50 & 60 mph in drive with moderate acceleration. Tach moves approximately 200 rpms and can feel the surge in vehicle.  Above 60 mph - no surge.  I have some mechanical abilities.  Check Engine Light is NOT lit.  Any ideas appreciated.

Answer
Are you actually telling me that you have 85000 miles w/no maintenance done on the vehicle ?.

Surging can be caused by numerous possibilities such as:

1. faulty, cracked, Broken vacuum line(s) anywhere on the engine.

2. Old, Tired, Worn out plug wires and plugs.

3. Fuel restriction, Partially restricted fuel filter.

4. carbon buildup within the air induction system.

5. partially restricted air cleaner.

6. Intermittent faulty TPS of which may NOT in alot of cases illuminate the check engine light.

7. Intermittent faults in the emissions control system.

And numerous other possibilities.

I suggest that you start maintaing the vehicle at recommended intervals.





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