My new 331 has finally gotten sick

[Obsol3te]

Well ran flawlessly except for an exhaust leak up by the headers that wouldnt go away even after a new gasket swap.
Guessing it's the headers, but here's the question:

Car is missing for no reason at all, and the thing is.
Not all the time either!
It'll run flawlessly, normally and how it just does and was day to day.
But then it'll start "missing"
You give it a little gas to help you cruise and it's backfiring. Doesn't really want to move anywhere.
But if you give it more gas, it'll "miss" more and get up to speed.
But I don't really want to do that.

Then it'll go back to normal after a few mins.

It doesn't do it at idle(unless it's very very very faint)

Everything in the engine bay is basically a year old or less, besides the pullies and wiring.

Got a complete MSD Ignition, last year
6al box, Billet dist, 8.5mm wires.
Running autolite copper 24's(just replaced)
Plug Wires don't look that bad, I do have a split boot on the 8th cylinder.
Very bottom of the plug and not too big at all, so don't think that could effect it.

And like I said, car was running fine.
Matter of fact awesome until a couple days ago.

Any suggestions?

 

[powertrax91]

i had most of the symptoms you described on both of my cars and both time it turned out to be dirty fuel filters... start with the little stuff first....change the fuel filter

 

[Grn92LX]

What heads are you running? Check for codes? A wideband would possibly help nail down the issue. With out my wideband and my PMS, my car would be junk!

 

[ZetecF1]

Make sure your Negative battery cable is properly grounded to your engine.

When I installed a new engine I had the same symptoms and that's what it ended up being.

 

[Obsol3te]

i had most of the symptoms you described on both of my cars and both time it turned out to be dirty fuel filters... start with the little stuff first....change the fuel filter

Replaced last year, didn't do too many miles on it.
But I'll pickup another.

What heads are you running? Check for codes? A wideband would possibly help nail down the issue. With out my wideband and my PMS, my car would be junk!

AFR 185's, Not pulling any codes.
And don't have the cash for a wideband, but was tuned via dyno a couple months ago.
Havnt done anything since.

Make sure your Negative battery cable is properly grounded to your engine.

When I installed a new engine I had the same symptoms and that's what it ended up being.

Now here's what it could be.
Sanded down where I have it ground in the back(battery moved to trunk, grounded to floor...)
Drove around the neighborhood, was fine.
Drove up the street and got on it a couple times.
Perfect.
Turned around to head back home
Does it for a min or two.
Then stops and I pull into my driveway.
Going to pickup some 00 Cable and run it straight to the block.
I have aluminum heads, so where would be a good place to ground?
Also will try a new Fuel Filter.
But AutoZone is my only option
and it'll probably be like Valucraft or something.

 

[Grn92LX]

Ok, well you have the WRONG spark plugs in first of all. You need autolite 3924's, NOT autolite 24's. Thats one problem fixed

When you move the battery to the trunk you have to go with good wiring and big gauge.

 

[universalstang]

I got a question, sorry to kinda high jack your thread.

I have autolite 25's thats what napa recommended.

I have high compression and 185's also. Also XE 282 HR cam.

would 24's work better, cause my car sometimes back fires out of the carb, then runs fine?

Thanks...

 

[Grn92LX]

Universal- you NEED autolite 3924's for your car, NOT autolite 25's. Don't listen to what the idiots behind the desk say.

 

[Obsol3te]

Universal- you NEED autolite 3924's for your car, NOT autolite 25's. Don't listen to what the idiots behind the desk say.

Are the 3924's Copper?
I need 1 step colder copper plug.
Thought the 24's were That.

 

[Grn92LX]

The 3924's are a longer reach plug which is what you need with alum heads. The 24's you have now aren't all the way in the chamber enough. 3924's are what you need for that n/a combo. I run them in my TW heads and have been for the past 4+ years.

 

[Jeff7477]

wtf is a 3924?

I always use 25's

 

[universalstang]

Im gonna switch to the 3924 tomorrow, I'll start the car and tell you guys how it runs. Might fix my over heating problem.

Thanks Green

 

[Obsol3te]

I do run a small shot of the n2o
and would like the safety of a step colder plug.
Are those, 3924's colder and copper?

 

[Grn92LX]

I do run a small shot of the n2o
and would like the safety of a step colder plug.
Are those, 3924's colder and copper?

Then use autolite 3923's if you spray the car. How much of a shot? Gap them smaller too.

 

[Obsol3te]

Nothing much, a wimpy 75 shot.
Might as well list my combo:

r331 AFR 185's 8.5:1 comp
75 dry nitrous, edelbrock performer rpm upper/lower
Egh, screwit if interested, www.cardomain.com/id/obsol3te

 

[Grn92LX]

Why such low compression? The 3924's may work, but i'm not sure exactly. Its only a small 75 shot.

 

[Obsol3te]

The low compression is for future plans, Single Turbo + Decent amount of boost.

And I know it's only a small 75 shot.
Hence me saying I want the safety of a colder plug.
Don't really want to melt one because of having the normal heat range.

 

[331 stang91]

After I swaped my motor I had the same problem. It turned out to be my fuel pump. Put in a new 190 and it ran fine. good luck

 

[jaymac]

First of all, if you had made the damn sig like your sig says you're "doing", you could've saved yourself alot of extra typing and gotten more efficient repiles more quickly.
But nobody knew your CR, your 75 shot, you tune, etc.
It's not just for show, brotha, it's to help us to help you!!!

Anyhow, did Menard's call you back about the bumper?

 

[jaymac]

After I swaped my motor I had the same problem. It turned out to be my fuel pump. Put in a new 190 and it ran fine. good luck

Oh, and he's already got a 255 lph pump, but YOU WOULDN"T KNOW THAT BECAUSE HE CHOOSES NOT TO HELP US BY POSTING A SIG SO WE CAN KNOW WHAT WE'RE ACTUALLY WORKING WITH!!!!!!!!!!!!!!