96stang3.8

I Just bought a 96 Mustang with 119,000 on it. When I was looking at the car There was a slight miss and the SGS light was on. Took my handy dandy Torque app and it told me there was a Bad O2 sensor.

I took here home and changed the Pugs wires and o2 sensor.

After I got the car home and let is sit for a couple of days in the garage I went to take her out. There was a Good loud tick coming out from under the hood. Took my other car and got a buddy with a stethoscope. While listing to the car the noise did not seam to come from inside the engine. And the Misfire was back cylinder 4. (around where we thought the noise was coming from.)

As we were looking at it the noise started to get softer.. Took the car around the block a few times and the noise was gone along with the misfire.
Cleared the codes and drove around for 20 min. not a problem.

Let the car cool off for a day or so, go and start it back up and the noise and misfire are back. and codes come back miss on 2 and 4. Let her warm up and all is just fine.

Would the Header gaskets be causing the noise on start up if they were leaking? (noise sound like a lifter knocking)

Should I look into replacing the ignition coil?

petrock

Sounds like a leaky hydraulic lifter or an oil pressure problem. It is taking too long to pump up the lifter and get to zero lash. So the connecting rod is banging up against the roller rocker causing your ticking noise. It is normal for hydraulic lifters to bleed down when the motor is off for a while, but they should pump up pretty quick once it is running again if you have good oil pressure.

It could be something as "simple" as it just has some gunk inside of the lifter that is not letting it pump up like normal and just needs to be disassembled, cleaned & reassembled. This kind of thing is a good reason why regular oil changes are important so that gunk doesn't have a chance to build up.

At a minimum, it might be worth popping the valve covers off, putting some cardboard on the bottom edge of the head to prevent any flying oil from getting on the exhaust etc, and run the motor a little while to see if you can further narrow down the problem. It will also give you good insight into how well the motor was maintained. If there is a bunch of sludge on the roller rockers & springs etc then the previous owner probably didn't change the oil as often as he/she should have. That sludge can cause all sorts of oiling problems.

Good luck...

96stang3.8

The oil pressure gauge reads right in the middle.

I think the noise is coming from the Drivers side. I don't think the valve cover will come off with out taking the plenum off.

96stang3.8

Listing to the engine with the stethoscope did not reveal any thing.

96stang3.8

The Misfire came from the fact I got a bad plug.

Old plug ... Run fine .... New plug ... missfire, Old plug ... Run fine .... New plug ... missfire

Must have just got a bad one.