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I know this is the 7th gen forum, but there are some mechanically adept people on this site so I was wondering if they could help me out. Here’s some background--I have a 1968 Mercury Cougar with a 390 engine, modded with ported and polished heads, headers, dual exhaust, Holley Street Dominator intake/carb, a C-6 tranny with a shift kit. Now here’s the problem--it pulls fairly good through first, then after it shifts into 2nd, it seems like it chokes itself out and it stops accelerating, then it seems like the engine "hibernates" cause when you try and give it gas it doesn't rev or anything, it takes time then it seems to "wake-up." The carb was rebuilt about a year and a half ago. It used to pull extremely hard up to third, now it can't even chirp when it goes into 2nd....Thanks for looking!

 
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has this been going on since the carb was rebuilt? if so, i would be suspicious, and say that whoever did the job didn't do it right. otherwise, check and see if the fuel filter is dirty

 
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I was thinking the jets are too small, never really drove it hard after we got it rebuilt. Place we got the kit from probly ordered the wrong rebuild kit. I guess I'll just take it to a performance shop and see what they say, bye bye $$....

 
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Check if you secondaries are opening up correctly

 
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What's a carburetor?

Like trashguy said, it sounds like the secondaries arent opening up. When you hold the tranny in 1st at 2000 rpm and punch the accelerator (with the air cleaner temporarily removed), you should be able to HEAR the secondaries kick in with that waaaaaaaaa sound

either that or the timing might be screwed up 'cause you probably have mechanical advance and points in your distributor

 
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Oh another thing im not sure if 68 fords have it but my 63 ford has a vacum advance which is how the timing advance works.... If your 390 has an vacum advance just pull it out it usally has 2 pins and a clip holding it in. Should be a diphram looking thing attaced to you distributor. First try suckign on it... if the diaphram seems to function properly it shoudl be ok... If not you will prolly have to special order one because they are rare little things you cant go pick up form the local Parts shop.

 
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I'll try to see if it's those secondaries later today, if the problem is that they arn't opening up, what do I have to do? Thanks for the help!

 
Rep Power: 323

if your secondarys are not opening up then most likely its the linkage, usually something is loose and binding or a clip fell of and its not hooked up at all.