85 GT intermittent miss at highway speed

[Noobz347]

Let it run for 10min… no sparks or anything coming out of engine bay with lights off. Probably not related to my issue but I’ve noticed since I’ve had this car… quite a bit of smoke coming out of pipes and it smelly. Smellier than my 91 for sure.
View: https://youtube.com/shorts/H_pxQw8ANQY?si=leMGZng68m146OaI

How long does the car normally sit? I mean... White smoke and water during a cold start on cool day, produces water with an emissions cam.

If you go out and drive it around for 15+ minutes and still have a [lot] of white smoke then that would be interesting.


"Smelly" how? Like... rich?

You said codes... This is an 85. Is it CFI?

 

[rwordenjr]

How long does the car normally sit? I mean... White smoke and water during a cold start on cool day, produces water with an emissions cam.

If you go out and drive it around for 15+ minutes and still have a [lot] of white smoke then that would be interesting.


"Smelly" how? Like... rich?

You said codes... This is an 85. Is it CFI?

It does reduce after a drive but still has a consistent cloud. Yea I'd say it smells rich and yes 85 CFI.

 

[Noobz347]

Hmmmmm....


@General karthief Ain't it amazing how these unicorns show up in groups? Who we got that knows CFI?

 

[rwordenjr]

Hmmmmm....


@General karthief Ain't it amazing how these unicorns show up in groups? Who we got that knows CFI?

Hmmmmm....


@General karthief Ain't it amazing how these unicorns show up in groups? Who we got that knows CFI?

I couldn’t pass on the car but it’s testing my patience lol.

 

[Noobz347]

I'll just say this and you can do some research:

If it were mine and I were keeping it, I'd convert that thing to a [modern] CFI or...

Essential Parts List​

1. Carburetor: Holley 600 CFM, Edelbrock 1406, or equivalent.
2. Intake Manifold: Edelbrock Performer RPM or Ford Motorsport.
3. Fuel Pump:
   • Mechanical: Carter M6624 or Holley 12-834.
   • Electric: Holley 12-802 with a regulator (5-7 PSI).
4. Distributor: Duraspark II or MSD Ready-to-Run.
5. Ignition Module: If using Duraspark, get the Blue or Red strain relief module.
6. Throttle Cable: Carbureted-style throttle cable (from a carbureted Mustang).
7. Fuel Lines & Regulator: Adjust for 5-7 PSI fuel pressure.
8. Kickdown Cable: Lokar AOD TV cable if using an automatic.

You'll probably pickup 25 crank HP in the process.

 

[rwordenjr]

I'll just say this and you can do some research:

If it were mine and I were keeping it, I'd convert that thing to a [modern] CFI or...

Essential Parts List​

1. Carburetor: Holley 600 CFM, Edelbrock 1406, or equivalent.
2. Intake Manifold: Edelbrock Performer RPM or Ford Motorsport.
3. Fuel Pump:
   • Mechanical: Carter M6624 or Holley 12-834.
   • Electric: Holley 12-802 with a regulator (5-7 PSI).
4. Distributor: Duraspark II or MSD Ready-to-Run.
5. Ignition Module: If using Duraspark, get the Blue or Red strain relief module.
6. Throttle Cable: Carbureted-style throttle cable (from a carbureted Mustang).
7. Fuel Lines & Regulator: Adjust for 5-7 PSI fuel pressure.
8. Kickdown Cable: Lokar AOD TV cable if using an automatic.

You'll probably pickup 25 crank HP in the process.

Thanks for the info, I will screenshot that for future. Right now I'm just trying to get it running good. 86k miles. Take a few days but I'll get the spark plugs out and post pics. I'll replace them either way because they're either original or close to it. I could see they're motorcraft when I swapped the plug wires... Those were original too marked 1985 on them. Same with the ignition coil stamped 1985 which I think still works because changing that didn't improve anything.

 

[General karthief]

Mentioned earlier, check the ignition switch under the dash for burnt wires and connector, check the plug on the coil too.
The CFI is mysterious territory even for experienced mechanics, I think the air/fuel system is not the issue here, seems to me to be an electrical issue,
Look under the car, does it still have factory cats?

 

[LILCBRA]

I wouldn't be surprised if the problem goes away once you swap the plugs out if you think they're the originals. It could be that one or more of the porcelains are cracked. It could be that anyway.... had a very similar issue probably 30 years ago with new plugs. Apparently they had bad porcelain or had micro-cracks. The problem went away once I finally swapped them.

 

[rwordenjr]

Mentioned earlier, check the ignition switch under the dash for burnt wires and connector, check the plug on the coil too.
The CFI is mysterious territory even for experienced mechanics, I think the air/fuel system is not the issue here, seems to me to be an electrical issue,
Look under the car, does it still have factory cats?

Okay will check ignition switch. Electrical Plug on coil is good, clean contacts and wires. And yes it still has factory cats

 

[2000xp8]

I had this issue back in the day, drove me nuts.
It was the spark plug wires.

 

[rwordenjr]

I had this issue back in the day, drove me nuts.
It was the spark plug wires.

i installed brand new wires but no help. hopefully spark plugs?

 

[2000xp8]

Maybe, but i'm not so sure in my entire life replacing a spark plug on any type of engine has ever fixed anything.

 

[rwordenjr]

Maybe, but i'm not so sure in my entire life replacing a spark plug on any type of engine has ever fixed anything.

thanks. only thing that improved anything was moving the spark wires to make sure 1/3 and 5/6 didnt come close to eachother. that was still with the original spark wires from 1985. I replaced wires thinking would fix it completely but no dice

 

[Noobz347]

Maybe, but i'm not so sure in my entire life replacing a spark plug on any type of engine has ever fixed anything.

We've all rubbed that genie bottle with [great] enthusiasm!

 

[limp]

Maybe, but i'm not so sure in my entire life replacing a spark plug on any type of engine has ever fixed anything.

This car used to foul plugs every other day.....

 

[rwordenjr]

First plug out. Not the originals but I think these due for a change… gap is .65

 

[Noobz347]

That one is pretty old. It's seen some pretty lean conditions too.

Is the oil on the threads from penetrating fluid?

 

[rwordenjr]

That one is pretty old. It's seen some pretty lean conditions too.

Is the oil on the threads from penetrating fluid?

I did not spray any penetrating fluid. Just unbolted and took pic

 

[Noobz347]

I think that oil is from the outside going in. If not, the engine is tired [and] running lean.


Will have to see what the others are like.

 

[Noobz347]

How many miles?