I have a 79 F100 with the original 302 with about 150000 miles
It was my step father's before me and I am the third owner
Enough with the introduction

When I got the truck it ran great but had a rusty gas tank that would clogged fuel filters and destroy fuel pumps
I went theory three pumps and about ten filters before I could get aroud to changing out the tank

During that time it sat a lot and now it runs kinda crappy

I have done a full tune up and it still has a miss to it
If I hold a sheet of paper to the exhaust it will suck in time with the miss
At normal driving speed the trucks runs great and turns over with about half a revolution when the truck is just slightly warmed up

But it will not idle without surging in drive
I cranked the idle speed up a bit to get it to stop stalling at idle under load

The tune up helped immensely but it still has that miss

A mechanic friend thinks it is a stick valve but has not had the time to run compression checks

It also thinks that possibly because two plug wires were very bad it is p[ossible that I fouled the plugs associated with those wires
(The plugs were replaced about 150 miles and one hour of idling before I replaced the wires cap, and rotor)

He has suggested running Marvel Mystery Oil through the gas and oil to see if just possibly the problem will correct itself before we tear into the engine

Any suggestions or thoughts on his advice

 

Another quick question

I was went ahead and did the Seafoam in the vacuum line trick that I found elsewhere on the forum

How long does the truck billow smoke afterward

Inquiring neighbors want to know

I can not possibly drive this thing on the road without getting pulled over for obscuring vison of the other drivers

 

Ok, welcome to FTE. I'm glad to see that you are taking pride in this truck. Not enough of these Dentsides are still around. I had a similar problem on my '82 with a 302 in it. I had rust in my front fuel tank and it clogged the fuel filter up. So I changed that. It helped alot. Then that shaking/missing at idle under load came back. So i changed all my spark plugs. That solved it. The gaps on the plugs the previous owner had done were all over the board like 52's and 48's and stuff when its supposed to be a 44. and with your spark plug wires being in bad shape its deffinatly possible to foul those plugs. Basically the easiest way to solve this and find out if there is a deeper problem is to change plugs again. And this time also get a new set of spark plug wires. This will hopefully solve your problem. Also i would like to see a picture of this truck. Sounds like it might be in pretty good shape.

 

It's in fair shape
Before my step father died he had started using it as a work truck so there are some scratches and minor dents
We were supposed to restore it together, but I have just been able to get started recently
I have to restore it or let it rot in my yard
It's jinxed
The man dad bought it from was an old friend who bought it the day he retired
He sold it to my step years later and three months later he died
My step father had had it for about ten years or so and three months after I got it my step father died
I'm either going to keep it till I'm 80 or sell it to someone I don't like

There is also rust in the usual places but not bad
Paint is still original and all one color which is a change for me
And as with all the other four trucks I had since he had one particular bull, there is a dent in the side from where he rammed me
Dad had that truck for the whole time that that bull was alive but a week after I got it he head butted it like he did every other truck I ever drove out there

But as a testimony to the strength of the old steel he barely dented this one
He cave the whole side of the drivers door on the 84 Ford and the passenger fender of the 84 GMC that my step father left behind again about a week after I got it, and he almost flipped the Ranger

Anyway
Yes I already have the new set of plugs
But are you saying that I need to buy another new set of wires

I also just fond a pretty significant leak in the carb base gasket

I just need to find out what carb I have so I can get a kit
The tag on the carb is gone but there is a sticker that says it was rebuilt by Holley with the numbers
64-5089 I am assuming that that is the model number

 

wow, odd story but, yeh thats still wierd. but if the plug wires are somewhat in bad shape i would go ahead and replace them. if they are in ok condition, there is a question are they faulty? To check go out side when its dark and start the truck up open the hood just enough to see the wires if there is an electrical arching go get new plug wires they are bad. but if not they probably are alright. also open up the distributor cap and check the coil make sure it aint burnt up. Now about the carb i googled the number and this is what i got.

Holley 64-5089 - Holley Remanufactured Carburetors - summitracing.com

that is a 2 bbl Ford Carb. That they put on 302's in 1978 so i guess someone got an older carb and put it on there. but either way, just take your carb off of the intake. go down to the local parts house and get a new carb/intake gasket. slap it on there. that will help your carb base gasket leak problem, if im understanding you correctly.

 

I don't know about the seafoam thing, but I would definitely check the plugs on the miss. I had just put new wires on my truck and it had a miss. So I checked the wires first by substituting one wire at a time and test driving it around the block. It still had a miss after I had went through all the wires one by one. So I new my new wires were ok. Then I did the same thing with the plugs I'd pull one out and put in a substitute and drive it around the block. Come to find out one of my plugs were bad. Now it runs great. Good luck!

You can also pull the plug and hook it back to the wire and hold with some insulted channel locks or something one by one and see if they are getting fire.

That vacuum leak under the carb might be the whole problem.

 

The wires are new put them on yesterday after the plugs did not fixed the problem

It's getting late but tomorrow I'll be changing the plugs with a set that I personally gapped

I did pull the others when I changed out the wires but istopped after checking the side opposite the miss for some reason and they were all good
I suspected that they like the AC Delco set I bought were not gapped properly
The ACDs were set at 65 but the AutoLites that I had out in last wee were all at about 44
I didn't think about the bad wires causing the plugs to foul

But after smoking the neighborhood out the truck is running much better

The only sprays I had available were starter fluid, that I used to need to start the truck cold, and break cleaner

I sprayed the starter fluid at the base of the carb and there was a dramatic surge
Supposing that it was possible for mist from the starter fluid to be affecting the carb I used brake cleaner at the very base of the carb and there was a surge that was very noticeable but not as dramatic, which i would expect

That and the faxct that if I crank up the idle spped just a little it runs flawlesly until I oput it in gear
Then the only way to get it to stop surging is to crank the idle back up to around 1000 (by ear) which will be around 200 when I put it in park

And thanks for the confirmation on the part number
That will make it easier to get the kit
My friend should be able to get it at jobber cost

I'm starting to enjoy this
I haven't really worked on cars since this truck was new

 

oh i know its fun isnt it. i love just tinkering with these ole trucks. they are so much fun to mess with.

 

yeah
I'm actually getting excited about rebuilding a carb, even though common sense tells me to just buy the rebuilt one

he last one I did was in high school 30 years ago
back then it seems like I did about one a month