Ok, my mild lil 350 is bothering me. Here the last week or so it seems to be running a little poorly. Fuel milage seems to have fell off a tad (could be imagination but it seems poor none the less).

350, HEI, holley 650 spreadbore, 700r4 tranny

1) Every so often it will start idling higher, like the throttle isn't coming back all the way...but upon inspection it is coming back all the way...even when idling higher pushing the throttle linkage on the carb doesn't change it.

2) After turning the engine off it diesels a moment. Does this like every other time or 2. Sometimes it doesn't.

3) When driving it feels really sluggish...kinda like the way it feels when I have an entire car load of friends (a couple of which aren't all that light)

4) Seems to get a little worse once the engine is completely hot.

So far the only thing I've really done is play with the idle mixture skrews. The first time I did this it seemed to help, but all of a sudden it started again and now adjusting seems to make no difference.

What else should I look for/try?

Normally I would call my dad, but he's not available as of now.

From what you just described i would be 75% sure you have a vacuum leak somewhere.

Shawn

From what you just described i would be 75% sure you have a vacuum leak somewhere.

Shawn

That's kinda what I'm thinking, where should i look and how should i go about it?

Inspect hoses for cracks? Isn't there something I can spray at the base of the carb to find if it's there (brake cleaner or something, i cant remember)

yea i usually use ether or carb cleaner. Spray around the base of the carb and above the intake ports ect. Dont know if your using vacuum spark advance or brake booster, but all are potiential spots. If your using a pcv valve they can be the culprit too. Then again you could suck air from the underside of your intake blah blah man sometimes its tuff. You could also have a fuel supply issue causing it to run too lean ect. This stuff can get a bit tricky been ages since i have messed with those spreadbores but i have hehe.

Sorry cant be of more help

Shawn

Check the springs in the distributor, make sure one hasnt broke or fallen off, not letting it return to 0* mechanical advance, doesnt hurt to squirt some WD40 in there once in a while to lube things and keep moisture out.

I agree with all of the above.

Vacuum leak.
Mechanical advance sticking.

Also, make sure the distributor itself is bolted down firmly. Could have advanced or retarded itself a bit or something crazy.

Possibility of bad gas, but the whole idling up thing (which I've never really seen with bad gas) has me pointing squarely at vacuum leak or mechanical advance problems.

Problem started before I filled up this last time and it's still doing it, so I doubt the gas thing as well. Looks like I'll look for vacuum leaks. Thanks guys, I'll let you know what I find

Could we rule out power valve or is still a possibilty too?

Found no leak around the carb, all the hoses looked good cept the vacuum advance had crack at the end so I cut off the tip and put it back but that didn't help.

While idling at least the secondaries seem to be closing all the way so I don't think they're sticking.

Distrib. is tight, can't easily pull the cap to check out the guts though.

Forgot to spray around the intake manifold.

I'm going home this Thurs. so it looks like before we head to dallas for the NHRA this weekend my dad can look everything over in the distrib/ intake/ ect and we can go ahead and check all the plugs and do compression checks, the motor has just under 30k now so it can't hurt to look everything over really well and tune it up.

I was just hoping to pick up the fuel milage I seem to have lost before that 300 mile drive.

Also put a wrench on your intake manifold bolts. I sprayed WD-40 all around the intake area and it never changed the idle. I finally put a wrench on all the bolts and 3 of them (in a row) were loose. I tightened them up and a vacuum leak that had plagued me for a year went away. Car was like brand new again.

Don't take anything for granted.

Also put a wrench on your intake manifold bolts. I sprayed WD-40 all around the intake area and it never changed the idle. I finally put a wrench on all the bolts and 3 of them (in a row) were loose. I tightened them up and a vacuum leak that had plagued me for a year went away. Car was like brand new again.

Don't take anything for granted.

will do

well its been a couple weeks since I didn't get to go home like I planned

the other day I revved and heard a pop or 2 through the exhaust around 4k RPMs, so I started being gentle on it, then....

All of a sudden last night I got in the car and noticed a considerable amount of power was back, no more dieseling, more throttle responsive...seems pretty well back to normal. So I know my problem isn't major, whatever it was.

Is it possible something was stuck in the power valve keeping it from closing or something like that? I've driven through 2 tanks of gas since I posted this problem, done plenty or hammering just in case something was stuck. Dunno why it decided to work again...but I can't stop smiling.

If I had to guess I'd call it feeling like a 20 HP gain or so. Very noticeable amount of pull in the midrange and a lot crisper response everywhere else.