neocrynym

Lately my TSX has been running a little rough, mostly at idle. Normally idle is smooth as silk, but recently it's been choppy at times. Not bad, but intermittently I'll feel the idle inside the cabin (a mild shaking), and when I do, it's a bit choppy. Basically, it feels like the car is running on 3 cylinders and wants to die, but it never does die. Acceleration is usually smooth, but sometimes it will stutter (feels like mild misfire).

So, my question is, should the car trip a CEL if it were running on only 3/4 cylinders? I would think it would, but my experience is all w/ OBD1 cars, and OBD1 cars can often be running on less cylinders and it will never throw a CEL. Only way you'd know is by how the car acts.

Also, with the seldom stutter when accelerating...this could be caused by running 3/4, but I also haven't owned my TSX long enough to know if this could also be caused by the drive-by-wire. From what I understand, DBW creates a much less smooth acceleration than a traditional throttle cable would. If the car were misfiring under load, would it trip a CEL?

Oh, it's an '04 6MT, btw. Has about 70k on it (I just changed oil, MTF, plugs, and air filter...but the problem is still there). Temps here have been cooler lately, but not much (in the 80's as opposed to the 100's it was all summer). Any help is appreciated, thanks!

poltergeist

Yes, if the engine had a dead cylinder, the check engine light would be on and flashing, and it would run REALLY rough. Even a fairly intermittant misfire will get picked up by the PCM and store a code & turn on the CEL.

More than likely if you've got an idle vibration with no CEL, it's an engine mount problem (or if the car's ever been in an accident) a bent subframe/front body structure that can cause an engine mount to be side-loaded and transmit vibration into the veh.

A little idle vibration is normal and can change based on engine loading (AC, P/S, alt. loads etc.)

neocrynym

Good call...I can see how it could be motor mount related. Car has never been in an accident, but at 70k, maybe the mounts are a bit worn?

Only conern is that if the idle issue is mount-related, this doesn't explain the occasional hiccup/stutter I'm getting when accelerating. Maybe this is just one of the downfalls of drive-by-wire: lack of smoothness?

matvey

I think it's normal if the engine hesitates SLIGHTLY once in a while at certain RPMs. It's happening on my TSX once in a while and I think i've experienced it on my CL and Accord as well.

MBA

EJH

First thing to check is the spark plugs, then your vacuum hoses, if they're in good shape then it could be a dirty throttle body or failing throttle position sensor, or lots of other stuff. These things may not always cause a CEL until they get really bad.

neocrynym

This is what I'm hoping it is. Maybe I just got a bad batch of gas or something too, lol. Happened on my hatch before. Boost + bad gas =

And to the other post, spark plugs are new and checked all hoses, etc. It could be a sensor...I guess only time will tell.