Running rough
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Elder User
Joined: Oct 2006
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Running rough
Hey all
2 Summers ago i had a job as a laborer at a construction company. The ol 300 came in handy! Let the truck do the dirty work rather than strapping drywall to the roof of my mustang lol. Anyways, it idled a little high, but for the most part ran as it should. Returned 15 mpg mixed, maybe 18+ pure highway. I was happy with it.
Last summer I had an internship and i basically didnt drive the truck. Drove the stang or my motorcycle. The truck sat for 6 months or so. Occassional use, but not everyday.
My stang has been down whilst i swap the heads and intake. Ive been driving the truck since its my backup vehicle for this kind of situation, and it has been running really rough. It wanted to die at idle so i adjusted the idle screw to get it back up to 700-800 rpm, but it pulls about 13 inches of vacuum at idle. Once moving, it has a hesitation unless im accelerating. Cruising / maintaining speed makes it hesitate.
Oh, and on my last tank, i returned a whopping 6.5 mpg...Im getting 460 gas mileage without 460 power damnit!!
I know the usual responses will be 1) check for vacuum leaks 2)seafoam it 3) remove engine and put in a $5000 rebuilt 300 with all the goodies, but i was wondering about the carb. I bought a rebuilt one form autozone last year. Do they do sloppy rebuilds? Ive honstly been considering just throwing the top end in the trash and getting the Offy/clifford intake and a 4 bbl carb, but those cost a bit more than im willing to spend right now. How hard is it to rebuild the carter 1 bbl? Could that be what i need?
CLIFFS
Truck runs like crap. Rebuilt carb from AZ last year. It sat for 6 months and is now running like crap and getting horrible gas mileage. Rebuild carb??????
TIA
2 Summers ago i had a job as a laborer at a construction company. The ol 300 came in handy! Let the truck do the dirty work rather than strapping drywall to the roof of my mustang lol. Anyways, it idled a little high, but for the most part ran as it should. Returned 15 mpg mixed, maybe 18+ pure highway. I was happy with it.
Last summer I had an internship and i basically didnt drive the truck. Drove the stang or my motorcycle. The truck sat for 6 months or so. Occassional use, but not everyday.
My stang has been down whilst i swap the heads and intake. Ive been driving the truck since its my backup vehicle for this kind of situation, and it has been running really rough. It wanted to die at idle so i adjusted the idle screw to get it back up to 700-800 rpm, but it pulls about 13 inches of vacuum at idle. Once moving, it has a hesitation unless im accelerating. Cruising / maintaining speed makes it hesitate.
Oh, and on my last tank, i returned a whopping 6.5 mpg...Im getting 460 gas mileage without 460 power damnit!!
I know the usual responses will be 1) check for vacuum leaks 2)seafoam it 3) remove engine and put in a $5000 rebuilt 300 with all the goodies, but i was wondering about the carb. I bought a rebuilt one form autozone last year. Do they do sloppy rebuilds? Ive honstly been considering just throwing the top end in the trash and getting the Offy/clifford intake and a 4 bbl carb, but those cost a bit more than im willing to spend right now. How hard is it to rebuild the carter 1 bbl? Could that be what i need?
CLIFFS
Truck runs like crap. Rebuilt carb from AZ last year. It sat for 6 months and is now running like crap and getting horrible gas mileage. Rebuild carb??????
TIA
Super Moderator
Joined: Apr 2004
Posts: 34,503
Likes: 2,820
If you checked the vacuum leaks (manifolds too), carb base, vacuum lines, brake booster, lines to controls etc, and you checked the ignition, try blowing a bit of carb cleaner in the carb. Maybe it breaks loose some crud, saves the rebuild. Fuel filter good?
FTE Legend
Joined: May 2008
Posts: 56,542
Likes: 0
From: In my own world
not enough vaccume, you have bad leaks, possible the gsaket between the egr, and intake, I'm sure you did'nt replace it when you did the carb change. bolts to hold down carb probably loose as well
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