Hesitation Puzzle-Solved!
 

Symptoms: Intermittent hesitation under acceleration. Only sometimes, and only after cold start. Would generally go away after traveling a few miles.

I was puzzled. Onset was very sudden.
Fuel pump and filter were relatively new.
Long list of possibilities came to mind, both fuel and electrical.

Then I noticed something very odd...
The hesitation happened when leaving work, but never when leaving home.
I started thinking ambient temp, and such, but that did not correlate.
On the 3rd day, I was forced to park in an alternate spot at work.
Guess what? No hesitation!
Hmmm!, I said...

Then it hit me. My normal parking space was inclined slightly 'nose down'. My alternate spot and driveway at home were inclined slightly 'nose up'. What could gravity have to do with it?

Have you guessed it?




That's right! Water in the fuel!!

The tank had been filled the day before the onset of symptoms.
Called the offending gas station about it. They were polite enough, but not exactly super concerned.

Can you imagine how many hundreds of cars in my town (very popular station) wound up with baffling problems and expensive service bills? Wonder what percentage of mechanics diagnosed the problem correctly...

Don't let it happen to you...

And I'll take full credit for assisting you in your diagnosis, most likely after reading my post about our Suburban ;). Now to get the water out!

csnow

Thanks for this post. It is amazing how these symptoms get translated into incredibly expen$ive parts/service replacment journeys.

My favorite is the woman who complained about not being able to drive her new car fully up her fairly long driveway. She said it always stop by "the tree". Always. Not at her friend's house, not going up into the hills, not going down hills, not anywhere but her house. No one believed her. She was outraged, frustrated and horrified that no one could fix it, let alone believe her.

The car was in the shop regularly for many weeks. There was a large bonus from the dealership and from the factory for the one who could figure it out. Techs came in on weekends and worked on it. Drove it up to her house ..... and sure enough, would stall at the tree.

It was even suggested, catch this, that someone should just cut the tree down! Got to laugh .....

The points, plugs, distributor, coil, wires, fuel distributor, fuel pump, fuel pump relay, iginition lock, fuse block, wiring looms, etc etc etc were all replaced. An incredible amount of hours, parts and frustration.

This was simply impossible. Not logical. Are there power lines near the tree? Is there a bump just before the tree? Is the car always warm before reaching the tree? Was she lugging the engine? What gear was she using? What type of oil, brand weight? Did this happen year around? Did she have passengers in the car? Was the trunk loaded? What was the weather? Had she ever washed her engine? Was the AC on? Was the rear window defogger on? Does this only happen when she drove the car? Were there crop circles near where she lived? You get the idea ....

It turned out that someone in the factory tossed a small ball of masking tape into her gas tank. Never created a problem until over time it started to expand and would wind itself around the fuel outlet and, with the proper inclination (her driveway), would starve the engine of fuel. A short incline wasn't enough time for the glop to move towards the fuel outlet. Her driveway was long enough to starve the engine of fuel.

The service manager was the one who figured it out. Carl Behr. He took a simple practical approach: Engine stopped receiving fuel. What causes fuel starvation?

He still has a small jar on his desk with the fuel and the continuing to expand small ball of wadded-up masking tape.

Haasman

Thanks for the funny story...

"...cut down the tree!"

Cracked me up!

Kinda reminds me of the story about the car that wouldn't start when the owner bought vanilla ice cream.;)

Yeah, I remember that one!:D

I remember that one too!