95' Formula with 95k. Water Pump #2 blew last month and took Opti with it. So I had the water pump, Opti, plugs & wires replaced together.

Now the car seems to idle rougher than before. More annoying is I feel a vibration from the engine when I'm at speeds between 50-55. Lower speeds and higher speeds run smooth and pretty. Any ideas what might be going on here? I took it back in to have them recheck the plugs & wires but they said everything was okay. Still seems like they screwed something up.

Any feedback would be greatly appreciated.

 

Are they positive the opti is in right? Also are they positive that the wires arent cross.

 

Sounds like you have a miss.

 

Is there any possibility the balancer is on wrong? Not sure with 1995's......

 

Correct me if im wrong, but doesnt the balancer only bolt up one way?

 

It'll only bolt up one way easily, but anything's possible with a little bit of effort.

 

From what they told me - they rechecked the wires & there was no cross
Not really a misfire. It revs in neutral fine... just idles rough and vibrates at 50-55 mph.

Thanks for all your input so far - I'm a very impressed first time poster

 

There is no "balancer".... its a harmonic damper. It will only bolt to the hub one way. But the hub has no "key", so its possible for it to turn on the crank. But it isn't likely to cause balance problems.

But I'd be inclined to look for a misfire as Rob/Shoebox stated. Cracked insulator on a plug, loose plug, incorrectly gapped plug, wires not arranged correctly and crossfiring, wire damaged by a pulley or the serpentine belt....etc. etc......

 

That's where I'd start my search. Don't rely on what they told you, the only way for you to be sure is to grab a flashlight, jack and jackstands and check it out for yourself! Good luck and post up if you have questions

Although it sounds like you have a misfire, a vibration can be caused by many things. Maybe your tires are unbalanced or worn (causes more problems than you'd realize)?

 

I'll have them check the plugs out thoroughly again.
Not the tires as they're fairly new and wouldnt cause the car to idle rough while at the light, etc.

Thanks again

 

Do you notice the vibration in a lower rpm vs a higher one?

 

Definitely a lower RPM
I can give you a specific range tomorrow if it would help

 

Mine did the exact same thing after a replaced opti turned out a wire melted so check those wires.

 

No, I was just wondering. My car does the exact same thing yours does but only in gear and when the engine is under 2000 rpm. I had a coolant hose leak and then I fixed it. The hose leaked a little (stress that) on the opti and ever since it stumbles and vibrates like hell down low. I can drop the clutch shift at the redline with no problem though. I would be inclined to think our problem is optispark. Maybe corrosion?

 

We're right on the same page here Stephen. Mine only does it when around 1500 RPM, and not a problem over 2000. Also much better in neutral (although still slightly present). It also only vibrates while accelerating around 50 mph... nada when my foot is off the accelerator.
I'd be pissed off if it is the Opti - although it's under warranty so I can take it back in there and get them to change it out.

Does yours only vibrate around a certain speed (~50 mph) or is it more at any time at low RPMs?