Mazda B2300 Has Very Little Power

I recently purchased a mazda B2300 truck. It is used. A 97. A lot of miles. It is an atomatic and 2 wheel drive.

I have changed the spark plugs and used a fuel injection cleaner.

The truck has very, very little power. It has a hard time getting to 50 mph. If it does get to 60 mph it makes a strange thumping sound. When I bought it heat was always on. That has been fixed. And there is a tiny radiator leak. Mechanics have looked at truck and said that is just the way with a small engine. I just don’t buy that. I have had push mowers that had more power. I am also getting terrible gas mileage. Only about 15 mpg. AArgh.

And you bought this truck for what reason? Did you test drive it? Did you experience the lack of power? And you bought it anyway? Please explain. Also please define “a lot of miles.” Do you know anything at all about the truck’s maintenance history?

The B2300 is a Ford Ranger in Mazda clothing. I’ve driven Rangers with 4-cylinder and V-6 engines. None of them, including the turbo-diesel Ranger (yes, there was such a thing, once), was limited to 50-60 mph. Your truck, assuming its engine isn’t totally worn out, should be able to keep up with traffic.

Any mechanic who tells you the truck doesn’t have enough power to exceed 60 mph is not to be trusted. This is totally bogus. You need to find a better mechanic.

I suggest replacing the fuel filter as a first step, and I’d wonder about the condition of the transmission fluid. Does the transmission shift smoothly?

Is the check engine light on?

There are so many possibilities here, and you’ve given us so little information.

I bought the truck because I needed it for work, and dump runs. And was desperate because I could not find anything in my price range.
Yes, I did experience the lack of power but thought it just needed a tune up.
It has 158,000 miles. It has been seen by 2 different mechanics.
The check engine light is not on. The transmission fluid looks fine. As far as shifting it seems to lag, when shifting into gears. It is an auto. I have not replaced the oil filter.
Thank you.

plugged cat ?
plugged fuel filter ?

Somebody could scan the codes. You could even do it with a 98 dollar scanner from Wal-Mart. Might help.

Spark plugs and fuel injector cleaner scratches the surface. And 158K is not a lot of miles.

Change the air and fuel filters. While you have the air filter off clean the MAF sensor (using MAF sensor cleaner - probably won’t help but it won’t hurt if you follow the instructions). You can also easily clean the throttle body while you’re messing with that stuff.

You said you did the plugs - how about wires? If not do those too. Don’t buy the cheap bottom of the line. OEM wires are probably not that expensive or just get a decent brand.

I don’t know what the ignition system set up is on that truck but if it is something like a distributor/cap/rotor you should look all of that over. It may have a coil pack and those can be tested.

When you are trying to get the truck to get up to speed what is the engine doing? Is the engine racing really fast but the truck doesn’t go with it? If so then this is a whole different ballgame.

I agree with ken.
Since the spark plugs have been changed already, my prime suspects would be a plugged catalytic converter and/or a clogged fuel filter.

Since the OP does not know the maintenance history, I would suggest changing the fuel filter immediately. Continuing to run the engine with a clogged filter will kill the fuel pump. Prompt action might enable the fuel pump to be saved.

If that doesn’t improve things, then direct your attention to the cat converter.
If it turns out to be the cat, then this truck will very quickly NOT be in the OP’s price range, unfortunately.

Thank you all for all the info. I will change the fuel filter first and take it from there.
When I am trying to get up to speed and I am looking at the rpms on the dash. It just seems to linger too long. Before changing into the next gear.
I will also see about scanning the codes.
Thank you.