Hello!
I recently purchased a 1994 Dodge Dakota with 78,000 miles on it. Everything seemingly works well, until it doesn’t. The issue is that when I was driving up a slight incline, I realized that it won’t go over 25mph. Put my foot into the throttle more, and it doesn’t go any faster. I can hear popping every few seconds, presumably a backfire, but not 100% sure. I took my foot off the throttle completely, and then put throttle into it again, and then it’s fine. when I get to where I was going, I turned it off and turned it back on. It’s fine for another 60 miles probably. This is a constant issue, but super super intermittent, with it happening every 60 miles. If I’m on the highway when this happens, I can put the truck in neutral, turn it off, and then restart it while driving. It’ll again be fine for another 60 miles. This happens when either cold or warm, and happens on any type of driving.
Here’s what I’ve replaced:
Crank Position Sensor
Camshaft Position Sensor (Pickup Coil)
Throttle Position Sensor
Spark Plugs (not wires)
Ignition Coil
I’m definitely forgetting some stuff, though.
Since it has been suggested on every forum, the fuel pressure is fine! Brand new fuel lines, so presumably a new pump and if it’s backfiring, then it’s getting fuel.
Have you cleaned your throttle body and airflow sensor? Checked air filter and fuel filter? Also are you getting any codes or check engine light?
on side notE I have seen the innards of a catalytic converter break apart. When going uphill whats left can turn sideways or slide back and block the exhaust. Sounding like a backfire and popping noise. Pressure builds up holding the broken piece against the outlet. Then after awhile of not running pressure bleeds off, once started gases can initially work around the broken piece, braking can make it slide forward, or going down hill. Until pressure builds up again. Not saying this is your problem but a scenario I have seen several times.
Forgot to mention, sorry. We have replaced the catalytic converter, too. The throttle body and air filter are fine. Not sure about MAF sensor, but maybe that’s worth looking at. No codes or any check engine light. Given it’s OBD1, my scan tool doesn’t show much in the way of diagnostics, either.
Just because you replaced the cat doesn’t mean you still don’t have an exhaust restriction. People don’t realize when they come apart they can throw pieces into the resonator or muffler. Replace the cat and still have a part clogging the muffler. Really need to determine if your exhaust is flowing 100%. You can drill a small hole after the cat or remove an O2 sensor and thread in a psi gauge. If it reads anything more than a few lbs you have a blockage.