85 GT intermittent miss at highway speed

[rwordenjr]

How many miles?

86k og miles

 

[Noobz347]

That's not a lot.

 

[rwordenjr]

How many miles?

Plugs 5 and 8

 

[Noobz347]

Those are more normal looking. Still show signs of being a little lean.

 

[rwordenjr]

Spark plugs changed… just test drove. It did it once in 5 min

 

[rwordenjr]

 

[Noobz347]

It looks to me like you're not getting enough fuel.

 

[rwordenjr]

It looks to me like you're not getting enough fuel.

That would cause intermittent miss only at certain rpm at certain speed ? That’s what nuts about this. It’s very specific conditions to make it happen

 

[Noobz347]

Wait for some more opinions to come through this evening but my next step would be to rebuild the carb and check for vacuum leaks.

 

[85GTStangGuy]

.... my next step would be to rebuild the carb and check for vacuum leaks,

Agree (other than it's actually a throttle body). I'd think that would be a good thing at this point in it's life...

More Information for STANDARD MOTOR PRODUCTS 1522

 

[General karthief]

Agree (other than it's actually a throttle body). I'd think that would be a good thing at this point in it's life...

More Information for STANDARD MOTOR PRODUCTS 1522

Not a bad idea

 

[Noobz347]

Agree (other than it's actually a throttle body). I'd think that would be a good thing at this point in it's life...

More Information for STANDARD MOTOR PRODUCTS 1522

Tomato/tomato pineapple/hand grenade whatever

I'll rephrase: Convert to carb

 

[AeroCoupe]

The other thing about all of this is the ECU harness is almost 40 years old and most likely brittle. The one on my 83 T-Bird was and it had all kinds of bare spots on wires. Pulled the CFI system off and went carb and never looked back.

 

[rwordenjr]

The other thing about all of this is the ECU harness is almost 40 years old and most likely brittle. The one on my 83 T-Bird was and it had all kinds of bare spots on wires. Pulled the CFI system off and went carb and never looked back.

One issue with me swapping to carb… is the state I live in. I won’t be able to pass smog. CA

 

[AeroCoupe]

Interesting. So even though they came stock with a carb on stick cars you cannot swap due to the VIN showing it is an automatic with CFI? Can you swap it to 89-93 injection?

 

[rwordenjr]

Interesting. So even though they came stock with a carb on stick cars you cannot swap due to the VIN showing it is an automatic with CFI? Can you swap it to 89-93 injection?

Correct. And I don’t think you can swap anything on it legally unless you use parts that are “CA legal” stickered which are premium priced. For example… there is only 1 street legal CA x pipe with cats and it’s $2K +

 

[AeroCoupe]

So can you swap it to a factory injection setup off an 89-93 car?

 

[Noobz347]

Can you swap it to 89-93 injection?

That would suck so much balls to have to do. lol

 

[gkomo]

Correct. And I don’t think you can swap anything on it legally unless you use parts that are “CA legal” stickered which are premium priced. For example… there is only 1 street legal CA x pipe with cats and it’s $2K +

Ooo I have that x-pipe and yes it sucked major balls to have to buy.

 

[rwordenjr]

Just installed that Renan distributor with new pip and tfi… car running even worse now. Idling so low so in park, sluggish. I correctly set timing after installed diz. Wtf !