1999 Honda Accord Violent Bucking/Surging

Here is a recovery from last site that did not get transferred over. The hashed lines mean a separate post.

and so a far while has passed and many observations taken. We did have the fuel system pressure checked, and that was good. didnt do it while driving, but we had put extra rpm on it while it was sitting in the shop. We did replace the fuel filter, and in this cars case, it was part of the sending unit, which we had to buy from the honda dealership, at about 70 some bucks or so. that did not fix the problem, but the car did gain some significant power, especially during the low rpm ranges. I never wiggled the key around, but ive never heard of that kind of problem before, however i will give it a shot. The bucking still exists. I have also noted the exact time it will also occur, as to before i never found consistency.

Another thing to mention as to what the surging feels like, and it may get better suggestions. Imagine pushing the gas pedal down, then all of the sudden you have power, then it goes away again, and wash rinse repeat. And note that this only happens when the car has not hit the further explained idle rise (next paragraph).

What happens is that we have to warm the car up as if it were winter. Then we just let it idle until we feel the idle getting rougher and rougher, and then the rpm will shoot up to about 1300-1600 by itself and then settle back down to 750 where it idles perfectly from there. if we let it sit also while hot, say going to to a department store and coming back out within 20 minutes, we have to wait for that rpm shift then its fine to drive again.

After the rpm rise and fall, the car will drive like normal, as if nothing is wrong.

That leaves me with these two guesses: A catalytic converter, or even an o2 sensor, even though it isn’t throwing a trouble code.

My knowledge of Catalytic converters is that it may cause poor performance, stalling, or surging and may smell like rotten eggs (which Tyler’s car does not have a foul smell like that).

And another thing to note: the way it warms up, it seems as if the car forgets how to idle at low rpm and has to reset or relearn that timing. very strange problem that is just pulling my hair out, and i usually do not have this much difficulty on these subjects, considering i do a lot of my own car work.
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New symptom we did not have, unfortunately it did not repeat. A few days ago we had a no start, with it turning over great, but NO HINT OF TRYING TO START. This makes me think it was part of the distributor(there was a ton of dew that morning) like either the ignition coil or the igniter. A;so, these symptoms of a no start seem to only chilly “dewey” morning. Didnt happen on a chilly dry morning.
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the second no start we tried 7 or 8 cycles of turning over for 6 seconds, then turning the key off and then back to starting to re-pressurize as much fuel as possible. then it started. Im thinking spark, because we have fuel pump engagement and replaced the in-tank fuel filter.

If there is any inexpensive way of testing each component of the distributor, let me know what is needed to test it. I have a fluke multimeter, id need to buy a test light, spark tester, and probably something else, but no idea on how to test an ignitor.

And, we have been checking mpg averages, and have been getting an average of about 26.5mpg driving nicely.

I drive the same way, and my car is the same car except in a 1994 vintage, and I get 34mpg combined.

Also Eric, your previous post on wiggling the key didnt make a difference. if we just lightly moved the key back and forth, the car did not want to stall.