Trucks been a sputtering

[CG]

My trucks drives round town just fine, but when I get up to freeway speeds she'll sputter now and again. I figured something wrong with the dist. Finally got off my lazy rear and popped the hood...blah..still has points dist. I swear the original owner told me he upgraded to HEI.

So Ive been putting off doing the HEI upgrade, but today I needed to go to the dump. So I figured I would just put new cap, rotor and points in there for now. Pulled off the cap and looked inside...yep a little worn...went to pull of the rotor, one of those round ones...it had studs coming up from underneath with nuts holding it on. Weird and then I noticed there were no points??? Turns out its a Pertronics distributor set up.

I tossed a new cap and rotor on there and it zooms right on down the road with no more sputtering at cruising speed. Damn happy I didnt have to put points in it or do an HEI upgrade.

The one thing I do wonder though is if this is the reason my tach is sometimes right on and sometimes waaaaay off.

[Twisted78SS]

CG, I had a setup the same as yours, and always figured I had a bad ground somewhere, Never could get the tach to behave the same way consistently. I did find the issue later on, it had a chafed wire that was occasionally shorting on the housing. Once I fixed that, it was rock solid.

[CG]

Originally Posted by Twisted78SS

CG, I had a setup the same as yours, and always figured I had a bad ground somewhere, Never could get the tach to behave the same way consistently. I did find the issue later on, it had a chafed wire that was occasionally shorting on the housing. Once I fixed that, it was rock solid.

Ill look for that. Its an all new instrument cluster. Maybe when I put it in I semi pinched something?...thanks.

[oldiron]

Great news! Now you can haul my 71 K10 to my place and pick up your Caddy!!!

[67CHIP72]

I'm still running points that I replaced in July because of sputtering. Still don't know when I'll go to HEI... Wish I could answer your tach question, but I don't have one and don't have an answer.

[CG]

Update....Drove my truck all over the place, around town freeway etc with zero problems. Today I went to go pick up my granddaughter and the darn thing started that missing sputtering thing again when I got up in the 50 mph range. Ill drive a ways and then it has a quick little miss...drive a ways and maybe a bit more of a miss...then nothing for quite awhile...blah.

On the one hand I love old trucks and cars, on the other hand it sure is nice getting into a new vehicle and just driving without worries.

Guess Ill check the plugs and wires tomorrow. Getting on a ladder to work on 4x4's is such a pain.

[shooterpcb]

How's your fuel pump? ..but if it accelerates good, probably not the fuel pump. Any plugs fouling on exhaust or anything? bad gas?

[texanidiot25]

If you don't mind driving it a little hard, give it the beans and see if it's sputtering and choking out at high RPMs just before it shifts. I know I'm starting to have carb trouble (in my case, dirt) when it can't pull WOT in 2nd, as it wants to hit third.

If it was the Dizzy, in theory it should have the problem at the same RPM no matter what the speed of the car. When my '90 Firebird's ignition trouble started, it would miss fire at 1500 RPM, and bog at 2-3k rpm no matter what speed. Couldn't cruse at 45 and couldn't accelerate much in traffic. 2 plug wires arced and the Dizzy was bad.

But in theory your problems should arise no matter what speed your at, but by the RPM if it's ignition.

One way to check plug wires for arching is to get a squirt bottle and spray around the wires, and watch for the arching to start if you have holes in the plug wires.

[spinning wheels]

My truck did the same thing. I tried everything from replacing fuel pump and fuel lines, nothing helped.

Finally one night, after dealing with the truck running fine, then sputtering for no reasons, I opened the hood. Wow, it looked like a sci-fi movie.
The plug wires were arching on the exhaust manifolds. When the wires were moved away form the manifolds, it ran great. But, when they got close to the manifolds, the lighting show would start up. I installed some new plug wires and better guides to keep them away from the manifolds.

After that, the truck ran fine, until...

[CG]

It runs great around town, never a problem. Its a K20 with a 4spd. Doesnt sputter when bringing the rpms up hard. Just cruising down the road at freeway speeds.

Ill be checking plugs and wires tomorrow.