Running crappy

[palallin]

On the 19th, I posted this to the "What did you do to your truck today" thread:

Originally Posted by palallin

Well, my truck woke up on the wrong side of the bed and ran crappy all day. Felt and sounded like it was running on maybe 6 cylinders or less. Exhaust smelled of less-than-fully-burnt gas.

So, when I got home from work, I started pulling things apart to see what was amiss. I noticed that the hose on the breather line from the air cleaner to the valve cover was separated from the steel elbow, so I pulled the cleaner off and then tried to pull the fitting out of the valve cover. It pulled the top half of the grommet off with it, so I had to pull the valve cover to fish the bottom pieces of the grommet out of the baffle. (I discovered in the process that I need new valve cover gaskets, but that's a project for another day.) I need to get a new grommet, obviously.

Then I pulled the distributer cap off (HEI). The center contact is burned, and the 8 wire contacts are pretty nasty, too. The center contact and the rotating contact on the rotor are also in bad shape. PITButt getting the cap off so close to the firewall.

So the next step is to buy a new cap and rotor. I don't know how much a coil is, but I think I might get one of those, too. These parts have bee there at least since 2003, maybe longer.

I am hopeful that this will cure the problem, but, even if it doesn't, it needed to happen anyway.

Well, it helped, but it didn't completely solve the problem: the truck still idles rough, stumbles, surges, just not as badly.

It sounds/smells like the gas isn't fully burning and sounds sort of like it needs to clear its throat--I bet many of you know what I mean. It may be plugs or wires, I suppose, and I will pull the plugs as soon as I can.

The day before, I filled the tank from nearly empty--I noticed no problems the rest of that day, but it was the next morning when, out of the blue, it ran poorly. I guess it could be some bad gas.

What else should I check? It's been years since I had to fool with this sort of thing, and I don't trust my memory.

[Blue/72]

Have you checked your spark plugs? One or two could be fouled

[palallin]

none of the plugs is fouled: all are a light tan color. Naturally, they cold all stand to be replaced, as they are at least 15 years old, but I don't see any obvious troublemakers. No sparking among the wires, either.

[midniteblues]

it sounds to me like you could've kicked up some trash in the gas tank when you filled it up.
i would check the fuel filters.

you said the plugs were a good tan color thats a good sign that junk didnt get caught up in the needle and seat in the carb.

make sure the choke is completely opening. that could be where your fuel odor and stumbleing could be coming from.

if its been since 03 i would double check the spark plug wires real good.

if your cap and rotor are burned check too make sure your motor has good clean grounds,its very often overlooked.

[Nufsed]

Use a DVM to check the resistance through the plug wires. I forget the spec but A.) they should each be about the same, and B.) they will be oh, maybe 50000 ohms each. As they age, the resistance goes up. I you've got any 100K ohm wires, you need a set.
Also, this increased resistance is what causes the contacts in the cap/rotor to get corroded and the carbon tracking to occur.

[n33k0]

My truck had a few similar symptoms yours is showing: Bogging on acceleration, surging at idle, fuel smell, it also had a very loud "tick" that sounded like a bad exhaust leak. I checked timing, plugs, PCV valve, choke, filters, carb...

The issue was my spark plug wires. They looked OK at a glance, and checking the resistance showed they were "good", but the plug boots were brittle/cracked and they weren't making full contact with the plugs causing misfires. Replaced all the wires and all the problems went away.

[palallin]

OK, so when it stops raining, I take a close look at the wires. I may also siphon out the gas and try a tank from elsewhere.

I will report back.

[palallin]

Thinking I need new plug wires, what HEI set best works? I've had sets in the past that didn't work well, and I don't like the universals.