When I start my truck it tends to no to stay steady.... When I step on the clutch to throw it into gear it begins to accelerate on its own...I'm hoping someone can let me know what it is that's making my truck accelerate on its own when I step on the clutch....

 

Idol: you don't tell which model year and how many miles are on the truck. I take a stab at it anyway: There is an Idle Air Control Valve sitting on top of the throttle body. I bet it could use some cleaning. This truck is the same a s the Ford Ranger 2.3L. This article applies:
| Repair Guides | Component Locations | Idle Air Control Valve | AutoZone.com

 

It's a 94 Mazda b2300 manual transmission 2.3 L engine..it has 180,00 miles on it I bought it used it worked fine up until 2 weeks ago it started to have this problem

 

It's a 20 years old vehicle. You cannot expect it to run without problems. The nice thing about this engine is that it is not hard to fix.

I suggest you don't buy parts and throw them on in the hope you get the problem solved. I suggest that you check everything, clean everything and reuse everything to see if it makes things better.

There is a whole list of things that can affect the idle behavior.
* vacuum leaks: trace all vacuum lines and see if any are broken. Clamp off vacuum lines near the intake to see if that makes the idle better. If that is the case there is likely a leak in that line.
* Ignition parts. I think your engine may already have DIS (Distributorless Ignition System) That means you need to look at the spark plugs and the wires. Our '97 has 8 spark plugs and wires. The ones on the exhaust side are easy to take out, the ones on the intake side are not so easy. Pull a few and compare them with a diagnostic chart.
Reference here:

https://www.mazdaforum.com/forum/maz...n-31499/page2/

If one plug is bad replace them all and replace the wires.

* Clean the MAF sensor with dedicated MAF sensor cleaner
* Clean the throttle body with dedicated Throttle body cleaner.

That's just normal maintenance. Start with that and report back.

 

Does the engine rev up or does the truck actually MOVE? If it moves with the trans in gear and the clutch in, your clutch needs adjusted, or one of the clutch hydraulic cylindars needs replacing.