318 runs great to 30 mph then dies

[The_Handier_Man1]

From: nvdesertrat0775  (Original Message)
Sent: 9/4/2001 8:58 PM

My 73 Brave runs great up to about 30 mph then throttles down, just as if I had killed the ignition. Sitting still, with foot on brake, it will race as high as I care to take it, w/o problems. It has the 318 with a new electric fuel pump (about 400 miles on it) and no apparent problem until I try to reach freeway speed.  I was returning from a short trip  and had no problem until it felt as if I was running out of gas, and actually had my highway assistance bring me out five gallons, which didn't help.
     The transmission fluid seems fine, which may still be part of the problem, since it's the load on the transmission that seems to start the trouble, but I have no idea how to narrow it down further.  Has anyone any prior problems similiar to this, or any suggestions how to isolate it?   

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I Had two occasions of this kind of trouble.  That is getting up to around 30 or 40 mph and losing power and putting it to the floor with no increase in speed.
     The first was back in the 50's.  After much frustration and a trip to three repair shops, I found (myself) that the rubber hose that connected the fuel pump to the gas line (from the tank) had a small crack in it.  When the engine got to that point of needing more gas, it was getting air instead.  Replaced rubber line and drove on.
     The second time was in 76.  The first truck I owned with a catalytic converter.  GG down the hy-way just fine.  All of a sudden started loosing power and slowing down. Wasn't long till had to pull off road.  Truck would idle, but put in gear and it bogged down.  Found that the convertor had stopped up.    DEL
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My problem turned out to be the ignition coil.  When it got hot, it simply wouldn't work.  Given time to cool down or replacing it with another, allowed me to drive home w/o problems.  Ray



From: dani147151167
Sent: 7/31/2005 7:02 PM

had the same problem turned out to be a dirty fuel filter



From: heynnema
Sent: 8/5/2005 5:56 PM

Well, your float level in the carb could be low. Try the drive again, this time with the engine cover off, and the air cleaner off. Get up to the speed where it starts to fail, then mash the gas pedal, and listen if you can hear gas being squirted down the carb's throat.

You might check your point dwell, and your vacuum advance. Do you have a timing light? Use that to check these.

You can also attach the timing light to any of the spark plug wires, get up to speed where it fails, and keep an eye on the strobe coming from the timining light to see if it disappears.

Cheers, Al