Car vibrating - terribly at highway speeds

[1BadBoy]

When I re-installed the fuel injectors after cleaning, I did have to remove the fuel pressure regulator. I was wondering what would happen if I removed the vacuum line while the vehicle was running. When I did so, the idling increased maybe double, but then came right back down when I re-attached the vacuum line. I don't know if that indicates anything really, but thought I would pass that along.

I'll replace the coil and igniter soon, and if it doesn't help, I'll grab a fuel pressure gauge and check that next. Thanks for the helpful suggestions.

[EyesofFreedom]

Well then the fuel pressure regulator is working then...right now my bet is on the coil

[1BadBoy]

Originally Posted by EyesofFreedom

Well then the fuel pressure regulator is working then...right now my bet is on the coil

I wondered about that . This is the same test I used on my wife's Taurus to check the PCV valve.

It appears the coil is the most likely candidate at this time. I'm going to pull off the coil and igniter tonight or tomorrow so that I can be sure to get the correct ones for the car. The Honda dealership gave me the part number, but said that the igniter can be one of 2 designs. And the only way in which they tell them apart is by visual inspection. He mentioned something about a "point" or "bump".

Thanks for the quick advise.

[EyesofFreedom]

Sometimes they will mark parts with a center punch...welcome to 21st century technology! lol! Just kidding. There is probably a different platform that the mount with...that is the drawback when the engineers change something in the middle of production.

[1BadBoy]

Probably just trying to keep everyone on their toes....

[EyesofFreedom]

that is just about it...I guess they never heard the old saying if it aint broke...but then again they have come up some some slick shi....

[Shirokaze]

Did you tell the dealer that it shook going up a hill? Thats what gave me the impression it was the axles before the rotation or balancing. Make sure you remember exactly what you told the technician or service advisor at any automotive shops/dealership.

[1BadBoy]

Thanks. I try to describe the situation the same each time, but human nature means there are some variations based on conversations. The interesting thing right now is that I had to remove both the igniter and coil to ensure I got the correct parts (ordered from RockAuto.com). After putting them both back in, the car is running better. However, to be fair, this has been an on-again/off-again situation for some time. It's just been getting worse over the last 3-6 months (more on-again than off). The parts have shipped, so I hope to have them this week and then I'll install. If this was an every-day driver, I would probably just order locally. I drive it mainly on the weekends, so leaving it the way it is doesn't affect me too much. Besides, I can always drive the wife's car .

I'll post again after putting the new parts in to let everyone know.

[dre5491]

i kno u prolly did this already but it could be sumthin as simple as tire pressure have u checked that?

[1BadBoy]

Sorry for the delay in posting my follow-up. However, replacing the ignition coil and igniter did *not* resolve the issue. After installing them, I took the car for a test drive and about a 10 minute drive on the freeway. All the way there, and then all the way back (on the freeway) it ran fine. But I noticed a slight vibration coming up a long hill from the freeway toward home. Not too noticeable right away, but after a short bit, it was back to its usual rough running (vibration).

Actually, at this point, I am leaning toward it being a "mechanical" issue. The reason I say this is that the vibration increases with the speed of the car and *not* with the speed of the engine. So when I shift into a higher gear (with the engine running slower), I would expect the vibration to slow too. It doesn't slow, though. And I've noticed that if I really pay attention, I can feel the vibration at slow speeds too, though it is noticeable at about 35 mph and faster.

If I am not accelerating at all (e.g. coasting or holding the speed steady), then there is little or no vibration. However, accelerating even slightly, uphill or downhill, causes the vibration to occur.

I am planning on taking the car to Les Schwab to have the tires and front end examined in case it could be something obvious. If they cannot find anything, then I'll have to find a repair shop I am comfortable with here in Seattle.

If anyone has any other thoughts on possible causes, I would appreciate any ideas at this point (e.g. CV joints, etc.).