Automatic carbed engine surging bad in cold weather help!!!

Ok Mazda guru's here's whats going on with my truck. First off it's a 93 B22 automatic trans, factory carb, everything is stock. The truck runs great in warm weather, but lately it has been running like shit! I live in Nebraska so it's cold. Anyways I let it warm up for about 15 minutes each morning and when I'm on my way to work trying to pic up speed I get up to about 40mph and the truck starts surging bad. I let off the gas for a second then slowly accelerate again and will make it to about 45 mph and start surging again. It acts like it isn't getting enough fuel. At first I thought maybe the fuel lines were freezing up or possible water in the lines so I added a bottle of Heet and it helped a little but still does it. I don't know much about carb'd engines or these trucks but a friend of mine is a mechanic and said he would say without looking at it the one or two of the injectors on the intake could be bad??? I'm not sure if he misunderstood me when I said it was carb'd or if there are actually injectors on the mani? Another guy I talked to said he would say it was a solenoid that went bad on the factory carb he called it a cold start solenoid. Anyone with any input or advice on this issue would be greatly appreciated as this is my daily and had to call into work today because I couldn't make it. So the sooner I can know what I'm looking for and get it fixed, the better! I'm not very familiar with these engines as I am a Honda guy, but if I know what I'm looking for I can usually fix it! Thanks guys!!!

You don't have injectors or a cold start solenoid on a carbed engine. You might have a crack in your distributor cap though. Not something you could see, but the cold weather creates extra resistance that the electricity has to fire through. I'd look at the cap or maybe a fouled spark plug.

Hope this helps.

It sounds like she is starving for fuel. Did you check/replace your fuel filter? It's a cheap fix. A semi clogged fuel filter can cause this issue. It's stock location is behind the gas tank on the passenger side.

I had a similar issue last summer. I had a hard time maintaining higher speeds, at lower speeds it was fine.

It could be be a "weak" fuel pump or clogged fuel sock in the gas tank.

Well I took my dizzy cap off held it up to the light and didn't see any light through it but noticed one of my plug wires tip was so far down in the boot that it can't make a connection or if it does it would be very weak. But I don't think that's it. I agree with you Dan, it feels like a fuel issue. It's just weird that it only has been acting up in this week since the weather has been down in the teens. In warmer weather I have never had this happen. Plugs have a heat and cold rating right? Could it be that my plugs have a hot fire and since it's so cold it isn't firing properly? I will check the fuel filter now.

I should have been more clear. Not a crack you could see through, but a crack like carbon tracking would make. Bad carbon tracking looks like someone has taken a pencil and drawn crazy ines inside the cap. And cold fuel doesn't atomize as easily as hot fuel does, so that adds extra work that the system has to deal with.

Alright thanks man well I didn't see any of that either. Now after removing my cap and plug wires the truck won't fire ugh! I'm positive my firing order is correct but I did however notice that my coil wire is jumping to the a/c tube when trying to fire so I believe I have a bad coil wire too. Could this explain the surging?

You may have found the problem. Anywhere the spark travels besides where it is supposed to go leaves less to fire off the mix.

Spark jumping is not good, sometimes can prevent an engine from running. Typical ways to check for this is to run engine at night, and or mist water from a spray bottle at the suspect area.

Alright thanks guys! I just went ahead and replaced the coil wire so far it doesn't seem to be jumping spark and runs a whole lot better. While I was at it I replaced the plugs, fuel filter, drained and cleaned the fuel tank, refueled with Shell Unleaded fuel (no more cheap gas), added Seafoam a few oz to the tank and sucked up a couple oz. threw the vacuum hose on the carb. So far the truck seems to be running as it should. I haven't noticed the surging yet. Today will be the test, I have a 2 hour trip and it is 5 degrees here so we will see how she does fellas.

You changed a number of things so you'll never know exactly what fixed your issue. Next time you may want to do one thing at a time, at least you'd know what you did to fix it.