Engine misfire? And a couple other odd issues

[L1011tristar17]

Over the summer my car has developed a misfire. It will misfire every 2-3 seconds when idling and it's enough to feel it through the floor/seats. There is a bit of hesitation when accelerating. Lately the shuddering has gotten worse and it still occurs every 2-3 seconds. It mostly goes away in neutral.

I had a full tune-up done 2-3 years ago, which was a new cap, rotor, plugs, and wires. Air filter and fuel filter were changed not too long ago. Is it possible that the plug wires are already bad? I don't know what brand they are, but they're blue with silver lettering. When I changed out the lower intake, the temp sensors looked crusty, but they seemed to work. IAC and EGR were cleaned and the TPS is brand new. No CEL and the only code is 34 (ever since I bought the car)

There are also a couple of other issues that may or may not be associated with the misfire. On a few rare occasions, the car bucks when trying to accelerate through second gear. It's bad enough that the car won't pick up any speed when I'm trying to accelerate. This happened once today after the misfire was worse than normal. The rest of the transmission shifts fine 99% of the time. Also, if I brake lightly to a stop, right before the car is at a stop it feels like the brakes either release or the engine surges. I have to press down the pedal further when slowing from 2mph to 0mph. If I brake more quickly, this does not happen. (I hope I was able to explain this clearly)

I'm not sure if any of these problems could be related, but it would be nice to get an idea of what it could be before throwing parts at it.

[gadget73]

Pull and check the plugs, especially the ones on the 2 back cylinders. If they are crappy looking, stab new ones in and see what you get. The ones in the back seem to oil foul more than the others for some reason. Not entirely sure if its PCV system or maybe just because the motor tilts that way and the oil runs past the valve seals.

[cld783]

lift the cap up to scrape the crud off the terminals and check the condition of the rotor. they dont last for shit

[gadget73]

especially the aluminum ones. yeah I scrape mine too once in a while.

[L1011tristar17]

Checked the distributor cap and it looked pretty clean to me. I gave it a once over anyways. The ends of the wires on the distributor looked good too. I popped each one off and checked to see that the metal terminals were in good shape. The misfire is still there and has gotten worse. Any other places I could look? I'll check the plugs this weekend.

[L1011tristar17]

I also checked the plugs. #8 had a lot of crud on it but I was able to clean it off. #4 was alright and I checked a few others and those were good too. I went to remove the plug wire for #3 spark plug and the metal inside the boot broke in half. So I'll be off to the store tomorrow for some new wires.

[GM_Guy]

Stick a NEW plug in the #8 hole. Sometimes cleaning will leave a conductive residue on the porceilain, especially if you used a wire brush to try and clean it.

Alex.

[L1011tristar17]

Good idea! I might just get all new plugs while I'm at the store. I didn't check all 8 plugs so who knows what the rest are like.

[L1011tristar17]

Put in 8 new motorcraft plugs today. The misfire seems to be gone if the car is in Drive but it misfires in Park. What should I look for next?

[sly]

cap/rotor and wires.

[gadget73]

Check fuel filter too if it might be considered vintage.

posting from mah phone. plz to be forgiving bad speeling.

[L1011tristar17]

Fuel filter was changed about a year ago. Wires are a week old. How do I tell if the cap and rotor are bad? I checked a couple weeks ago and visually I didn't see anything that was missing or gunked up.

[sly]

if the posts on the cap wiggle in place with little effort... replace it. If the rotor doesn't have a good T on the end of it and look like the stock photos... replace it.

[gadget73]

Fuel filter is an annual item.

posting from mah phone. plz to be forgiving bad speeling.

[L1011tristar17]

A little update: I checked the IAC (it was clean) and made sure all the vacuum lines were hooked up. I checked the timing and I noticed it was a little advanced. I bumped it back from 14 to 10. None of this seemed to make a huge difference.

The inside of the distributor looked fine. I noticed some fine metal shavings (like graphite). The rotor and contacts looked fine although there were burned spots in the center of each metal contact where the spark was made. Is any of this normal?