HELP! My ‘73 bronco looses power when going over 40mph

[Paula73bronco]

Hi, the guys from the full size bronco website sent me over here. so yesterday I brought my car to the mechanic because my bronco was loosing power while going uphill. Now it works perfectly fine uphill but I’m loosing power when driving on normal flat roads once I go faster then 40mph. It doesn’t happen every time but often enough and once it starts it doesn’t stop. I’m not sure what’s wrong with it but I’ve spent so much money trying to get it to work so I’d really appreciate some help or advice.

thanks

 

[m_m70]

Well welcome!!

Did your mechanic tell you what he did to get your uphill power issue fixed??

just a couple that come to my mind would be fuel filters, fuel pump, ignition/tune up, timing or carb adjustment to list a few.

There's a lot of different things this could be. To help us out, could you give some specifics on your truck??

Things like year, motor, upgrades etc. can really help out!

 

[thegreatjustino]

What did the mechanic you brought it to do? If he adjusted the carb or timing, it's still not correct.

Go talk to him again since he did not address the problem correctly.

 

[DirtDonk]

Welcome from here too Paula!
And when you say "losing power" doe you mean it just won't accelerate hard anymore, or does it actually slow down? Or does it stop running altogether and you have to stop and try to fire it up again?

As said, lots of things it can be at this point. But we can drill down (for free even!) and see if we can narrow it down to (hopefully) something simple and cheap to fix.

Good luck.

Paul

 

[Paula73bronco]

It’s a 1973 bronco ranger with a 92 inch wheel base, 4 x 4, power steering, hydroboost power brakes, 2 1/2 inch suspension lift, brand new 15 inch rims with 32 inch tires, original 302 engine with a rebuilt three speed automatic transmission, Dana twain transfer case, Dana 44 front axle, Ford 9 inch rear axle, all stock, other than the 2 1/2 inch lift and the oversize tires. Those are the specs from the guy I bought it from. So my mechanic has fixed the alternator and there was a transmission leak as well that he took care of he also came by yesterday to change the ignition switch cause it was getting stuck. Then I told him about the power loss issue u had and he switched around some gray small tubes (he’s not responding right now so I have no idea what exactly he did) I drove the car this morning for three miles to grab groceries and it was working perfectly fine. Then on the way back it almost felt as if I was taking my foot of the gas even though I wasn’t. I was still able to drive home without stopping but the speed went from 45mph to 30mph and the harder I tried pressing on the gas the more it would slow down.

 

[B RON CO]

Hi, it sounds like the mechanic checked out some vacuum hoses.
As mentioned, there are a few things that could cause a loss of power you are describing. I would focus on fuel flow first. I would change the filter(s), test the fuel pump, and gently blow air from the rubber line at the fuel pump back into the fuel tank. A good fuel pump should fill a coffee can with gas in about 30 seconds. Any mechanic with classic car experience can do this easily. Good luck

 

[Rightpace]

Find a new mechanic

 

[NGABronco]

If you have an auxillary gas tank, check the switch just below the driver seat to make sure it's in the correct position??? Good luck!!!;D;D;D

 

[Rightpace]

Sounds like an improperly performed tune-up.
Seriously find a new mechanic

 

[El Kabong]

It looks like you've found your way over. I'll just copy & paste my response from the other site, less the referral to CB.com.

Whenever I've had issues with speed or hill climbing, it's usually a fuel delivery issue. In my case, a partially clogged fuel filter. It flows enough for low engine revs, but not enough for higher speeds or demand like hill climbing. You could have similar issues with a partially clogged air filter. I'd start with changing air & fuel filters. Sometimes you will find 2 fuel filters. One directly into the carb & another in the fuel line somewhere along the way.


Thinking about it, once I had an in tank pickup do the same thing. It was clogged enough to keep the engine from running at speed, but not so much that it wouldn't run slow.


One more thought is venting to the tank. When fuel is removed from the tank, air has to be allowed in to replace the fuel. If the tank venting isn't working, vacuum builds in the tank, not allowing fuel out. An easy check is to pop the gas cap while it's acting up. If you hear a rush of air when you pop the cap, you know you need to resolve a venting issue. That might be as simple as changing to an older style vented gas cap.