Need Help

Need help I have a 1984 xlt 351 windsor 5.8

Every time i put her in gear she dies. She has a Holley street avenger 4 barrel 570 cfm.I believe its a vacuum problem,But dont know where to start 

Hey Rich, Welcome.

If you think it's a vacuum issue, start by looking at all the vacuum lines and fittings. Check all around the base of the carb for ports that may be left opened.

You can also start the engine and carefully spray carb cleaner around the base of the carb, and any vacuum lines. If the RPM increases you have your vac leak.

The brake booster may be leaking as well. crimp the vac line to the booster and see if the problem persists.  (remember you will not have any boost to the brakes, so this is just for diagnostic purposes.)

You didn't mention any other systems, like rough idle, / missing, or such, but this is a start.

If no vac leak is found, go back to basics and check the timing, mixture settings, EGR, Etc.

Also you may just need to raise the idle speed

Good Luck  

The idle was off, at times it would be high others it would be normal. I have to set the idle speed to about 2k to keep it running in park, but once I put it in gear it just stalls.

High = 1700 to 1900. Normal = 800 to 900. When I bought it, It did have a air/fuel mixture problem adjusted the carb a little and it ran fine for about 2 weeks. I did find 2 vacuum lines that go around the carb, but no where to plug them in.Tried to plug them and no change. Not sure if this goes with the problem but when I rev the engine the carb would back fire. but only when it was cold. And only once in a while I've owned it for about 3 months and heard it about 5 times

Backfiring is normally a timing problem.  There should be a timing setup procedure on the emissions control sticker which is normally on the passenger side of the radiator support. 

Good luck,

>-

As BB said do the timing check.  vacuum leaks can cause backfires as well.  

Be methodical and check the timing as directed on the emissions sticker. Have the engine warmed up. Check to see if you are getting advance as well with the spout connector in and rpm increased, or vacuum line back on the dist. ( I don't remember which you have with an 84.)

Check for vacuum leaks, as mentioned in my previous post.

Only after you have done those checks and corrected any faults go to the carb adjustment

Engine off turn each idle mixture ***** all the way in till it gently seats. Back them out 1 1/2 turns

Start the engine and adjust the idle to about 800rpm.

turn each mixture ***** out 1/4 turn at a time and watch for rpm increase. When the rpm no longer increases, turn each ***** back in 1/8 turn.  This procedure has gotten me as close to perfect idle mixture as one can get without proper exhaust gas analyzing equipment.  You can also add a vacuum gauge and watch for a gauge that's steady and between 18 and 22 inches of vac.

if you are good with the timing, and vacuum leak check, and idle mixture, you can then set the idle speed.

If you take shortcuts you can remain with problems.  

Since you don't have an all stock engine it is a little difficult to cover every possibility for you, but this should get you on the right track. 

Good Luck

Thanks for all the help. It turned out to be a vacuum line. But I do have another question how can you tell if the fuel pump is starting to go? Reason I ask is because I put a clear fuel filter on the line going to the carb, and when the engine warms up the filter just drains. and I get a little going back in not giving me enough fuel going to the carb. And if I pull the line off the filter it acts like vapor lock ? Any help would be great. 

"And if I pull the line off the filter it acts like vapor lock..."    I'm not sure what you mean by that, but there should be a check valve built in the pump that prevents the fuel flowing back.

If the pump can't keep fuel in the filter when running, I'd say it has gone bad.

Thanks that's were I ill start then