running way off on hg's and have miss

bryant10

Registered User
I have a brand new long block from ford well it has like 10k on it now. Did not run right when I got it back. After taking it back to them twice; Once to fix the rear main that still leaks and once for an idle problem which they said was cats and maf. I finally found a loose lower intercooler tube the bolts weren't even tight enough to stop the flange from rattling, after tightening this I finally got the car to run a 15.2 which isn't bad. But I expected better. I also have 4.30 gears and a 10% march pulley, removed air silencerand a 3" cold air intake. Last week for no reason I just got an irradic idle with not CEL it will die at stop lights it is so rough I have 10hg in park and 5 in gear sitting in the drive way. I can still get a good eleven to twelve pounds out of it which is all I ever got with my pulley which I don't comprehend. Would a miss from a plug or wire effect my boost or does this have to be a blown gasket or vacuum leak. 6 weeks ago my friend and I removed the blower and clamped all the vacuum lines and tightened the blower tubes. Any help would be great thanks.
 
You may have a vac leak. try spray carb cleaner on all the IC tube joints while the engine is running. What your looking for is a change in idle when you spray the cleaner, if idle changes then you have found one leak. Check all joints.
 
Here you go

http://www.sccoa.com/forums/showthread.php?threadid=19261

Ah, the SC engine. If this doesn't help, e-mail Vernon and he might know something else. There are so many places you could be getting excess air into the engine, and although the article is about boost, it works for vacuum leaks (most of the time).

Also, get a code reader even if you don't think you need it. It will run a cylinder balance test for you so you can see if one or more cylinders aren't contributing. That $20 piece has saved my *** several times.

Didn't know March made a T-bird SC pulley. If you don't have free flowing exhaust, get it now or get walking.
 
Like Mike said, it's a vacuum leak and most likely at the IC tube connections. I would reseal all the IC tubes with RTV (Permatex Copper Orange).

David
 
Thanks for the advice guys I will check it with some ether today and see what I can find. I do have some pretty free exhaust just drops to two high flow cats then two three inch glasspacks and dumps right there. this is a little loud on the highway esp with the 4.30 gears but it sounds nice in town.
 
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