frankenford

i call my ?89 f350 frankenstein because he?s pieces parts ?89 cab, ?81 engine, ?79 chasis? anyway, my point. just recently i was driving along (pretty hard) pulling a load. engine?s running crappy so i pulled over to check under the hood. well when i turned off the engine it backfired and blew apart my muffler. i opened the hood and my exhaust manifold was glowing red hot (it really scared me) so i took off the air filter i had recently scavenged from my other truck. i believe it was extremly cloged. sorry i did?t check it before hand with the flashlight test, like a bone head. anyway went to AutoZone. bought a Flowmaster and an Edelbrock 1000 cfm air cleaner, both now on the truck. by the way when i said running crappy i meant it was lacking power and missing, also back firing ever time i shut it off. it?s been a growing problem. this is a very hard working tree service truck the engine is a( 4.9 I-6 300) o.k. new exhaust, air cleaner, Accel super coil, Splitfire spark plugs, ignition module, and fuel filter (just a couple of weeks ago did oil change and put in Restore with the change, don?t know if that matters)(maybe i should have done a motor flush 1st) right so all those new parts and it runs like brand new, that is untill it heats up to 190 to 220 then it starts missing so bad it sounds like it?s running on 5 cylinders instead of 6. which it probably is. that is, only when idle speed or at stop lights. when it is under acceleration this does not happen. don?t know where to go from here! help!

Reply to
t-bone
Loading thread data ...

Catalytic converter if it has one.

Reply to
John & Heather Letendre

no cat. at all on it! that would have been my first guess as well. do you think the EGR valve could be sticking. maybe i burt up the gaskets on the intake/exhaust????

Reply to
t-bone

I wondered about whether your EGR valve may be opening at idle, but sticking will do just as well. You could probably take the vacuum off it and see if that makes a difference.

Reply to
Joe

Sounds like a burnt valve if only one manifold is hot. A compression test will tell. Had your symptoms happen to me on a 302 many years ago and one exhaust valve had a hole burned through it.

--Mort

Reply to
Mort

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.