Rough Idle
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Rough Idle
I have a 1978 F-250 with the 400 cid 100% stock with 77,000 original miles on the truck and 5,000 miles on the new long block (installed in 1998). It was running great until I ran one of the tanks completely out of gas. I switched it over to the other tank and ever since then, it has been idling rough when it is warm. It feels like its going to stall when I am at a stop light, but it just sputters. I have cleaned the carb, but nothing. It smells like its running rich.
I have knowledge with new engines, but I am pretty clueless when it comes to carb's. Any ideas as to what it could be? I was thinking that I may have clogged the fuel filter when I ran the tank dry, but it accelerates fine...
I tried searching, but nothing..
Thanks in advance.
I have knowledge with new engines, but I am pretty clueless when it comes to carb's. Any ideas as to what it could be? I was thinking that I may have clogged the fuel filter when I ran the tank dry, but it accelerates fine...
I tried searching, but nothing..
Thanks in advance.
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In reading other posts, I am thinking it may be a vacuum leak.. I did notice when I was working on it that the brake master cyl appears like it has a slow leak between it and the booster. Would that be a cause?
More Turbo
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From: New England
You would get a slightly higher idle (fuel starvation) for a vacuum leak. You can check by spraying some carb cleaner around the suspected leak (in your case between master cylinder, booster) and if engin smoothes out, then you found the prob.
My first thought was that when you switched tanks, you had some old gas in the other tank. If you only put 5,000 miles since 1998, I bet that gas has turned to linseed oil
That rich smell is the old gas. It doesnt burn completely because the petroleum distilates have conglomerated together LOL seriously. something like that goes on with old gas.
Try removing all that old gas, change fuel filter, put some fresh fuel, and take it out for a day's drive. If you dont drive it much, you should put some fuel stabilizer in both tanks to prevent the fuel from breaking down.
My first thought was that when you switched tanks, you had some old gas in the other tank. If you only put 5,000 miles since 1998, I bet that gas has turned to linseed oil
That rich smell is the old gas. It doesnt burn completely because the petroleum distilates have conglomerated together LOL seriously. something like that goes on with old gas.Try removing all that old gas, change fuel filter, put some fresh fuel, and take it out for a day's drive. If you dont drive it much, you should put some fuel stabilizer in both tanks to prevent the fuel from breaking down.
Last edited by fozzy; Dec 10, 2006 at 12:46 AM.
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I started driving it a few times a week since September. The problem didn't occur until the first part of December, so the gas should have been ok.
I have changed all the filters (fuel, air, breather) and replaced the PCV valve. I have also run the tanks to E and put 1 can of seafoam in each tank and added 10 gals to both the main and aux tank. Since then, I have run the aux tank out of gas, and i have about 1/4 tank in the main tank. The problem is still there.
I have noticed that the problem occurs only when the engine is at operating temp.
Any ideas?
I have changed all the filters (fuel, air, breather) and replaced the PCV valve. I have also run the tanks to E and put 1 can of seafoam in each tank and added 10 gals to both the main and aux tank. Since then, I have run the aux tank out of gas, and i have about 1/4 tank in the main tank. The problem is still there.
I have noticed that the problem occurs only when the engine is at operating temp.
Any ideas?
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Maybe look this page over to see if any jumps at you..... to consider ?
http://www.autozone.com/servlet/UiBr...3d800acdd5.jsp
http://www.autozone.com/servlet/UiBr...3d800acdd5.jsp
