Hey Yall, I have an 89 Dodge Ram with some issues. Basically i fixed the main idle problem cause the idiot who owned it before me replaced the distributor cap but put the spark wires in the wrong firing order. Now that thats fixed i'm havng some problems with highway driving. When im up to highway speed after about 30 min the truck starts jerking like it's hesitating then when i go down to slower speeds or stops after that it stalls on me over and over. If i let it sit for a while and turn it on, it drives fine at normal speed. As soon as i hit highway again, same problem. Any ideas? I'm thinking maybe fuel pumps having a problem. At highway speeds it uses up all the gas that gravity put there then the pumps fighting to supply more. Just a thought. Tell me whatcha think.

Thanks

 

might be a fuel filter

 

I agree if you haven't changed the fuel filter lately I would do that. Try removing the gas cap temporarily when it does this and see if the problem clears up.

 

Uhh, ya i replaced the fuel filter bout 2 weeks ago.

 

Try removing the gas cap temporarily when it does this and see if the problem clears up.

Look down inside the throttle body when the truck is running. At the base of each injector you should see a fine cone of fuel. The cone should be solid and even with no gaps or streams. The base of the cone should touch the sides of the throttle body throat.

You can tee a gauge into the fuel supply hose at the throttle body to check the pressure. Pressure should normally be 14-15 PSI, disconnect the vacuum line to the fuel pressure regulator and the pressure should rise to 18-20 PSI and when you pinch the return line to the tank the pressure should rise substantially to 40-50 PSI. If these pressures are met the problem is not likely in the fuel system.

 

If the fuel system investigation turns out ok, I would revisit the distributor again. Stalling unexpectedly, letting it sit for 5-10 minutes, starts up ok after, engine bucking. Replace the Hall Effect pick-up assembly. As they age, they tend not to handle the heat generated in there in addition to contact surface corrosion which adversely affects ignition timing. They begin to fail hence the stalling, poor running condition mistakenly attributed to a faulty fuel system (although not ruling that out). A faulty Hall effect pick-up will also not throw any codes, at least on the '88 TBI's

I recommend inspecting your spark plugs as well - check the gaps and overall condition. A new set is cheap insurance.