Macster, you're correct. These technically are not the correct plugs and I put in the correct Bosch's you see in the background there. Regardless, the car ran fine with them for ~10k+ miles.

They were close to being due, but it is not the culprit and that's what I'm trying to highlight here. The guys cleared the fuel line and test drove the car after and it ran fine, then we replaced the sender and plugs for good measure.

 

hmmmm...so if the fuel line was plugged how did you get any fuel through it? Or why just at 4K? Seems you have multiple failure mechanisms at work and we won't really know what fixed it as you changed multiple things at the same time (sender and plugs not to mention the fact you had to reinstall all of those items). Just saying...

 

Re-read a few posts back. They drove the car after unclogging the fuel line and it drove normal without the hesitation. We did the other items for good measure as we knew the fuel level sender was bad and I wanted to have the plugs done anyway.

 

OK, I did read it...again...perhaps I am illiterate, but you still haven't explained why if there was something stuck in the fuel line any fuel gets through...perhaps it was a small obstacle, but I don't understand why this explains the hesitation at 4K...I don't care that the symptoms are gone (that is NOT evidence of causal understanding), just that we understand what really caused it...I realize you really don't care about that and you just want your car to work, but for the benefit of the rest of us...we need further understanding of the issue...Or NOT...LOL. BTW you can ignore me, no hard feelings.