Random severe miss

[Stangman]

I could be driving the black car and it will run great, fine, like it always does... then out of nowhere it will just drop a cylinder!

It used to do that ONLY after a warm start-up after I've been driving it.

Now it will do it if I am driving down the road!

The other morning on my way to work it was running smoothly, then it would miss, then smooth out, then miss again... Did this probably 10 times before it decided that it wanted to permanently miss... ALL the way to work. But on lunch I started it and it ran fine. and has since. It is VERY sporadic.

Would this be an injector or FPR? or even a bad Holley 255 pump?

[Mista Bone]

Sure it is not spark to one cylinder breaking down????

Bad plug or plug wire???

How about spark jumping wires and causing early spark on one cylinder?

My Mustang Nightmare.....

[Ranger50]

Agreed, plug breaking down or wire grounding out.

Brian

[765Travis]

Possibly burned valve?

[mustangjon]

cruising rpm? does it do it under WOT, idle? ect

[RIXXX93GT]

TFI module.

[chad393na]

What car is it?

[Stangman]

my black '94 GT.

It will miss at idle, miss at cruising RPM and miss under WOT.

It is a DEAD miss. like someone reached under the hood and yanked a plug wire.

If it is a wire grounding, wouldnt it do it all the time? I don't think that it would do it, clear up, do it, clear up, do it, clear up, and then keep doing it.

And if it were a TFI module (I have an Accel on it now) how would it only make on cylinder drop?

I think it's gotta be after the distributor, or somewhere in the fuel system. The car has the stock FPR on it still... 222,3xx miles... If that has anything to do with it?

The thing sounds like a WRX STI on the inside when it misses like it does! :lol:

I drove it today, yesterday, and the day before without an issue... tomorrow it will act up! :rolleyes:

[Black Horse]

Does it only do it when it is cold (below freezing)?

Clean your MAF sensor, but I would be suspicous of the TFI or Hall effect sensor. Especially if it is getting worse. If it is the TFI module is will die completely at some point. If/when you replace the TFI, replace the Hall Effect Sensor as well as a failure of either component is known to take out the other.

Good luck.

[Stangman]

No it used to do it in the summer too.

I don't think I am understanding how a TFI module will kill only 1 cylinder though?

The miss will gradually smooth out, not just up and go away.

I will try cleaning the MAF sensor when I get some time.

[mb88coupe]

anything is possible with any electrical... ive seen alot of things that doesnt make any sense at all. tfi is what it sounds like to me or bad wire/plug to me maybe injector wiring ?

[facemelter71]

The TFI module controls cylinder firing and timing on the electrical side.The Profile Ignition Pickup (PIP) is inside the distributor and it is the hall effect sensor for the tone/window ring under the rotor button.Mine went out on my 86 and I just replaced the whole distributor.

I dont think this would be a fuel problem.As fuel would not cause ONE cylinder to take a dump,unless its a bad injector.If its a fuel pump it would have low power or run hot or probly not start at all.If the regulator crapped would make it run like ass and smell like raw fuel and probly burn your eyes when you walked behind it.

Have you checked to see which cylinder is dead? Pulled any plug's?

[Stangman]

Not yet. been waaay too cold, or waaay to busy to check it. It has been running great the past few days :rolleyes:

I do smell fuel though when walking behind it, heck I don't even have to step behind it to smell it! :lol:

But heck it's always done that.

[facemelter71]

Not yet. been waaay too cold, or waaay to busy to check it. It has been running great the past few days :rolleyes:

I do smell fuel though when walking behind it, heck I don't even have to step behind it to smell it! :lol:

But heck it's always done that.

I dont meen a little rich.I mean if some one threw a lit cigarette back there it might just go up in flames rich.

[Stangman]

If I had the car in the garage and sitting there idling my eyes would burn like a bitch.

[facemelter71]

If I had the car in the garage and sitting there idling my eyes would burn like a bitch.

Shit,you have a garage.Yank it in there.

I dont have a garage,I get to go out tonight and pull the heads of my coupe on my porch,outside.

[mustangjon]

you have to keep in mind with O/R pipe your gonna get that gas smell... and some cars worse than others...

x2 on a sensor.. hell my car developed cruising rpm miss recently, was fine wot, and idle... pulled codes and had smog, egr and tps... thought egr sticking... but i found a spare tps laying around and it seemed to fix it..