Honda-Acura.net - Intermittent Issue

I'm of the opinion that intermittent problems are the worst car issues that there are. If you got a problem, Car, then JUST FRICKIN' TELL ME!! Stop bein' shady about it.

Well, I've got one and I have no idea what's causing it. I seem to have a bit of stumble at lower RPM's and I can't figure out what the issue is. No common distinct set of criteria can be blamed... at least not one that I can see so far. It doesn't matter whether the engine is warmed up or not... whether it's hot or cold out... wet or dry... high altitude or low. She just sometimes seems to wake up in a cranky mood.

First things first, this is on a 1994 Accord with an F22B1 VTEC engine. My initial thoughts were ignition, so I replaced the plugs and wires... to no avail, of course. So far, that's all that's been done. Fuel filter is relatively new, too, though.

Originally, this problem only presented itself at low speeds when the RPM's were low. If you took off from a stop at a slower speed, only gradually pushing the throttle and keeping the RPM's low, there would sometimes be a bit of a stutter. It was faint, but distinct. But, if you pushed the gas pedal like you meant it and goosed the throttle to the floor, the car would take off and run like a raped ape, just like she's supposed to. It was an annoying problem, but it didn't happen all the time, so it wasn't one that I couldn't deal with.

Over time, though, the problem is getting more intricate. It's still an intermittent issue, but now it's not only doing it lower speeds. It's now graduated to being an issue that can and will present itself at any speed, but always where the RPM's are low. Setting my cruise control on the highway can even cause it. 25... 45... 65... speed doesn't seem to matter, anymore. Only RPM's.

The magic number on the tachometer seems to be somewhere between 2000-2500 RPM. Whenever it's below that, there's a chance that it'll stumble. Whenever it's above that, the car runs perfectly and you'd never know that there was anything wrong. I'll be cruising down the freeway or gradually accelerating from a red light, the RPM's will be low, and the car will start to shudder a bit and the speed will drop. If I push the throttle to raise the tach, it quits. If I upshift to raise the tach, it quits. Once I undo whatever I did to raise the RPM's and they drop, though, it's back. Sometimes when I'm doing this, she'll even threaten to die when I pull up to a stoplight (though, she never does).

Two more small things to bring up. First, sometimes you can put the car in neutral while coasting down the road, turn it off and restart it, and the problem will go away. Sometimes, you have to do that several times before it works, though. Also, I'm noticing that though the problem is usually present on start-up, sometimes it's not and will show up a little later... like when I'm bombing down the highway after having the cruise control set for twenty minutes or more.

Second, sometimes she backfires on me. I used to think that every time it backfired, the problem went away and she'd run like normal until the next time I shut her down and started her up again. Well, this may or may not have been the case in the past, but it definitely isn't a sure-thing anymore. Sometimes it quits running shaky after a backfire... sometimes it doesn't.

So, there you go: car stumbles and shutters intermittently at low RPM. My buddy swears up and down that a backfire always means ignition, but I'm not too sure. Whatcha think? Cap and Rotor? Distributor? Throttle position sensor? I'm at a loss, here, and I don't wanna just start throwing parts at it until the problem goes away.

One final point: sometimes it can go days without showing up. Sometimes when it does, it shows up once and goes away for another semi-extended period of time. Sometimes, it shows up and sticks around every goddamn time you start the car for days upon end. That's why this pisses me off so much: there's no pattern.

Thanks for reading. I hope like hell that a wiser fella than myself can make this problem a thing of the past...