unstable idle and stalling upon acceleration
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unstable idle and stalling upon acceleration
ok, yesterday my truck stalled on me after a loud boom came from under the hood followed by a cloud of smoke. surprisingly it fired back up no problem but after that the idle was jumping all over the place and it would bog down when id step on the gas. also i am now hearing a slight hissing noise when i go from idle to part throttle. i checked the compression and spark plugs and everything is normal, i also checked all bolts for tightness. the only thing i can think of is something inside the intake or carb broke. since ive owned this truck, theres been a small crack between the intake and exhaust where they meet, and it runs up towards the carb about half an inch. it has never caused any problems before, but its all i can think of at the moment. id like to buy a new intake/exhaust manifold and carb, can anyone suggest a really good replacement for this engine? my truck is a 1986 F-250 4x4 with the 4.9L inline six (300).
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Sounds like you blew out part of the intake manifold gasket.
The cheapo upgrade:
Pull the manifolds. Have the intake machined flat. Buy EFI 3 into 1 manifolds for the exhaust, and mount them with the stock intake. Replace all the studs and bolts for the mounts.
My studs were almost all the way out, and one of the intake bolts still works loose, making for a regular ritual to keep all 6 firing.
Worst thing about the engine, imo.
The cheapo upgrade:
Pull the manifolds. Have the intake machined flat. Buy EFI 3 into 1 manifolds for the exhaust, and mount them with the stock intake. Replace all the studs and bolts for the mounts.
My studs were almost all the way out, and one of the intake bolts still works loose, making for a regular ritual to keep all 6 firing.
Worst thing about the engine, imo.
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well.... i ended up caveing and buying the offenhauser c-series intake and some headman headers. i accedently broke the intake and exhaust manifold when i was trying to seperate them. ive worked with alot of cast iron before, and ive never seen it shatter so easy. ive been hearing some bad things about the headman headers though and its going to be a real pain in the *** trying to hook up dual exhaust, was it a good idea to get these? can anyone recomend a carb for me to put on this intake manifold, ive been reading holley 390cfm is the best for this manifold.
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