karnykamaro

95 z28 Lt 1 m6

One day drive fine started next day and there was a vibration throughout the car when I start it no problems starting just feels like a knock but when I stick my head under the hood no noises except for a slight tap on driver side front of valve covers nothing major it seems but the vibration is in time with the exhaust sound that I have. The more gas I give her the more predominate the sound. When driving it doesn't quiet down the vibration sound feeling whatever u wanna call it is more predominate when pulling up a hill or putting the car under more strain please help me out !!!!!

moparman

U joint causing the drive shaft to vibrate?

Injuneer

To be clear - the vibration is in synch with/proportional to engine RPM and exists whether the vehicle is stationery or moving???

karnykamaro

Yes

maybe2fast

Do you have headers? Y-pipe hitting the floor due to a bad motor or trans mount...ask me from experience

karnykamaro

No pipe is up I drove it today I'm thinking maybe a miss almost like a cylinder is down or something

karnykamaro

I check wires today at work they seem good its too cold with no garage to work in

Injuneer

Best time to check the plug wires is in the dark, after LIGHTLY misting them with water. Look for arcing with the engine running. You aren't going to be able to tell much about the condition of the wire just by looking at them, unless they've been clearly burned on headers, rubbed through by the serpentine belt, or just generally in rotten condition.

karnykamaro

Wires are new to describe it better u can say there's a harder pop to the exhaust sound then before and that's what I believe I'm feeling. Replaced wires opti water pump and I believe plugs but can't remember back In october

Injuneer

Sure sounds like a misfire - pop in the exhaust, more predominate when pulling up a hill or placing the engine under load. Make sure a wire didn't come off the plug, you don't have corrosion on the wire towers on the Opti, make sure a plug was not loose and popped out, etc.

karnykamaro

Will check into that as well today while at burger king I noticed the slight valve tap getting louder would that have anything to do with it

Injuneer

Sure. In incorrectly adjusted valve can cause misfires.

karnykamaro

So what's my easiest and cheapest course of action cause I think its that the more I think of it AND what would my course of action be to fix and upgrade the problem part everything is pretty much stock

Fatdog2

What condition are your plug wires?

karnykamaro

Brand new this past October have maybe 2000 miles on them at best