Hi there,
You said from your first post.
"That last note is probably the culprit (main fuel pump) - the pump is original (347,000 miles), but I just wanted to see if anyone had other advice. It seems like the car is running super lean. I probably forgot to add a few things - so ask questions if you've got 'em!"
Super lean! Yep, I am leaning alright, into what Art says, a fuel issue! No questions from me, just because of 347,000 miles on the original pump, yow!
I would have already changed out that pump somewhere past 250,000. Its been my experience that they can begin have intermittent issues, like hesitation to turn over at the first click of the key, when they get that old. Mostly due to worn brushes.
With this many miles on it you might have two things going on.
This is a roller pump which is pretty simple in operation. It is somewhat a positive displacement pump.
Lots of wear opens up clearances. The filter is where it is so that stuff stops there and not into the injectors.
347'000 has me thinking that you have probably lost a bunch of efficiency, just not dead, yet!
If you throw in those worn brushes, you should NOT have enough torque being generated to really run pressure up either. Pick a flavor!
That is, unless the pump itself is worn out so much that its bypassing fuel within the housing itself. All of it not going out but the pump hums.
It might explain why you are not hearing cavitation sounds, which are louder than normal, but sounds like an electric motor turning.
Yep, inconsistent buzz, I will buy into that game!
Advice coming at you!
Change out the pump, for the piece of mind. The pump owes you nothing. You are past any pro-rating and warranties. (:-)
I will also say that the firing up and running "consistently" is not an ignition issue. It's been my experience that ignition does not "wane" out. It misses or quits to function at all.
Do what Art suggest, I would.
There nothing like feeling a bulging going on and things are working well down there!
No matter where down there, is!
(:-)
Phil
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