Hesitation/knocks on auto-transmission shifting


was wondering if someone had any insight as to why the car (silverado chevy pick-up actually)knocks and hesitates(occasionally even stall-out) when the dew point/humidity levels rise- or after a rain- after running the vehicle for several miles and has heated up, the problem ‘seems’ to disappear. I know of another person w/ this problem(a different make/model however) but have yet to find a solution. Have tried dry gas and a high octane boost product but to no avail. thanx for any comment on this problem


You did not choose to share the model year or the odometer mileage of the Silverado with us, so my answer may not be valid if the truck is relatively new, but here goes:

What you describe is the classic symptom of bad spark plug wires and/or a cracked distributor cap (does your engine have a distributor??).

You should be able to visually check for the source of the problem by filling a spray bottle with water and by misting the engine at night. The areas where you have cracked insulation should show up visually when they are hit with the water mist.

So, if it is more than a few years old, I would suggest installing new spark plug wires. If it is still under warranty, the obvious answer is to take it back to the dealership for warranty-related repair.


Thanx VDCdriver- I will use the suggestions. it is a 2001, 4.3L, 2-wheel w/ 84K miles


The spark plugs are probably original. Change them while you’re in there. 84 thousand miles is long enough use on them; actually, too long ---- they’re are already contributing to the problem.