Weird problem....

[Undecisive]

Ok, this is kind of a long story, but here goes...

My 96 Tahoe threw a SES light last week. It started randomly missing. Not a bad miss, just sputters for half a second and is fine for a few miles. I got the code read at Advance, and he said it's a code for catalyst efficiency below threshold. That lead me to believe it was clogged cats.

I climbed under and took a look. Cats look original. My problem is I've lost no power and the cats aren't glowing or causing a sulfuric smell from the exhaust as is normal for clogged cats. Our main tech (work at a diesel truck shop) said it could mean it's either clogged or gutted, throwing off the sensor.
He is going to hook up his Modis to it and find out the readings on the sensors before saying the cats are bad. The smooth running (no bogging)and power lead me to believe it isn't a problem with clogging.

Now, we started talking and he told me the dist. caps on these (crab cap) are notorious for going bad. This one was not replaced with the plugs and wires. I started thinking and yesterday it was flooding when I was out driving and that is when the miss was the worst.

What is the best cap I can get for the money? I don't want to spend a ton, but I also don't want to swap them every month, seeing as how the cheapest one I found is $35. This may or may not be the problem, but since it hasn't been changed I want to swap it. He said people are bad about overtightening the screws and cracking the caps.

Anyone ever had a similar problem or any insight into this problem? I'm not sure which problem it may be.

 

[96ProCompTahoe]

the MAJOR prioblem with the caps on the 5.7's is they aren't sealed to the distributor. drive through a deep puddle, the steam will get up under the cap and corrode the points, i had this problem a few weeks back but mine was bad enough it wouldn't turn over. may have the same problem, but its not bad enough to notice power loss.

if its never been changed, or has been in the truck for a long time the torx screws on the rotor may be nice and rusted out.

i have heard rumors there's a new cap thats coming out that will offer a sealed fit over the current non sealed. you might as well just pick up the $35 one, as its more a common problem than i ever thought. (NAPA here in town sells out of caps when we get alot of rain...)

 

[Undecisive]

I'm buying the cap tomorrow. It's almost to the point of being funny, really. My tech at the shop told me to try something, and I am "almost" sure that's what it is.

He asked if it missed yesterday and I told him it didn't. The weather was crisp and cold and almost no humidity. He told me he was sure it did on the way to work this morning. And oddly enough it did. He said the humidity was 76% and that is what caused it. Then he said when we were getting ready to leave that it would be really bad on the way home. It was raining so I told him I'd see. Sure enough, it was a rough ride home.

I have a feeling moisture is getting into the cap. Because on a nice dry day, it runs great. Cloudy and humid or raining, and you can bet it will act up.

How big of a pain are the caps to change on these? I've always owned Ford and my last truck was a Ram, so I've never worked on a 350. I'm almost sure it can't be worse than a Ram.