New to this, so here's the deal. 1997 Accord EX V6 w/78K miles. No matter if it's hot or cold, rain or shine, lately and like clockwork, after 10-15 minutes of driving (no matter what the speed) my tach jumps wildly. Very soon after the tach hits 0 RPM and the engine starts to buck and stutter sporadically, but not violently. It remains until the end of the ride but never stalls, and the check engine light does NOT come on (The light does cycle through at startup as it should). My mechanics have no idea what it could be without the engine light triggering. The problem resets itself after the car sits for a few hours and then the problem happens again on cue. My question is which electrical/ignition part if any is causing this? The plugs/wires, distributor, fuel filter, PVC valve, O2 sensor, ground wires????? I'd like to try to fix the problem myself, keeping in mind I change the oil and filters and that's my extent of repair knowledge, but not afraid to learn. Thanks in advance, and any help or direction would be great.

 

i have the same problem with my 95 accord v6. I have read somewhere on a forum of someone else that had this problem and they had found out that it was the ignition wire that needs to be replaced. I hope i am remembering this correctly cuz this is a $25 part from honda. I have been searching to find that post in who knows what forum to verify it. My car usually doesn't do it, but it does occasionally. yesterday it did a lot, and also i felt it affecting the engine like how you described. but i filled up my gas tank and it didn't do it today. If you find out about this, post it cuz i need to know for sure too.

 

I just found one post about this problem, finally! It says the same thing that i said, that since the tachometer gets it's reading from the ignition coil ($83), it could be that. here's the link.

http://autorepair.about.com/library/faqs/bl830.htm
One more post about the same thing with someone that actually had the ignition coil replaced.

http://autorepair.about.com/library/faqs/bl041b.htm
if i find more, i'll post.
hope you found this helpful as i know i could used this info myself.

 

If the ign. coil was bad it would set a mil light, in my opinion I'm leaning towards a speed sensor. Erratic tach and stumbling is a common systom for a bad speed sensor. it's pretty easy to change and it shouldn't be too expensive.

 

In a service news article from Honda they say the following:


Tach Fluctuation and/OR A/T
DTC P0725: Accord V6

On 1995-97 Accord V6s, when you troubleshoot a fluctuating tachometer OR A/T DTC P0725 (lock-up clutch does not engage), keep in mind the cause could be a faulty resistor in the ignition coil. The transmission control module (TCM) provides electrical pulses through this resistor to drive the tachometer. Although a faulty resistor doesn’t affect the coil's ignition functions, you'll still need to replace the ignition coil to fix a fluctuating tachometer OR A/T DTC P0725 the coil resistor isn't available separately. Order P/N 30520-P0G-A02, for the ignition coil.

We had this happen on a couple of cars in work and replacing the coil fixed the problem.

 

After having the ICM and the actual tach replaced, and a bunch of head scratching, a Honda tech said " oh, that's the Ignition Coil". So, after the coil was replaced it has been fine. It wasn't the speed sensor, it was the IC. Luckily the ICM module and other crap was under warranty, as well as the IC. What got me was the timing belt at 79K. So, if anyone else ever has this happen, start at the Ignition Coil in the distributor.

 

I had the jumping tach needle problem for over a year, which developed into an intermittent ignition problem...misfiring etc. I replaced the ignition coil and the problem went away. The engine runs smoothly and the tach is steady. However, when I changed the coil I took the distributor cap off - it's mounted directly above the coil and is in the way. There was oil in the distributor, and quite a bit of oil that made its way out of the distributor and over everything underneath it. I see in the Helms manual that there is an o-ring on the distributor shaft. I'm hoping that all I need to do is get the o-ring replaced.