My 89 mazda b2200 is having throttle issues. Manual shift. When in neutral it seems as if the gas pedal is pressed slightly. when i start in first i dont even have to press the gas pedal. it will start moving by itself. Sometimes the throttle will stick wide open and the truck will accelerate by itself. When it does that i cut the truck off and crank it right back and it is fine. The butterfly is not sticking i do not believe. it seems to be free and moves smoothly. It does puff some white smoke sometimes. Any ideas would be appreciated thanks.

 

Hi JD:
It could be a sticking throttle, a vacuum leak and at that age just about anything else. Therefore I suggest to approach this from cheap to more costly.
Clean the throttle body with throttle body cleaner, such as CRC Throttle body cleaner. Clean the EGR valve as well. EGR ducts and ports may need a bit more aggessive solvents such as B-12 Chem Tool.
Make sure the throttle cable is not worn through anywhere and give it a good lubing. Lube the accelerator pedal linkages as well. Under the hood there could be a mechanism that slows the throttle return when you let go of the pedal. Anyway my 323 had that. Make sure it operates properly.
Check for vacuum leaks. Replace the old rubber hoses. Replace or at least clean the PCV valve.
clean the MAF sensor with CRC MAF sensor cleaner, don't touch the sensor wires with anything!
Check or replace the ignition parts.
Check the fuel delivery system.
Give it a seafoam treatment.

I am thinking if you go carefully over these things you may stumble on the actual cause. Good luck!

 

cant believe i forgot to mention it is a carburetor also. Ive already put seafoam in it. Think maybe its time for a carb rebuild?

 

Yes, a carb job might be a good idea. But first see if there is a vacuum leak at the throttle axle. For a short time I had a Honda 350 CL and I noticed the xles wore out the throttle body there.

 

Hey my truck started doing something different lol. Now it runs good sometimes and other times it will not idle. Like say im in fifth or fourth and i start slowing down to turn(after i pull it out of gear) it dies. This is very frustrating on a hill if you can imagine. I put some pictures up if anyone can tell me what the mixture solenoid is and if that could be my problem. The thing i have circled in yellow is not hooked up i was wondering if it needed to be.

 

honestly, I am not sure therefore the following are guesses. The last carburetor vehicles I had were without catalytic converters. The one I remember the best is of the VW beetle.
It had an automatic choke. It looked a bit like the triangular piece with the 3 Phillips head bolts. Inside of it was a bi-metal coil that was warmed by an electrical circuit. It opened up with the heat and also dropped the idle speed.
the was a vacuum pod on it which provided the vacuum to retard the ignition timing depending on throttle position.
It did not have a mixture solenoid. That mixture solenoid was probably needed to continuously change the mix from lean to rich in order to provide O2 to the catalytic converter.
The pieces you circled look unusual to me so they are likely the the mixture solenoid and yes, it should be hooked up.
Do you have a Haynes manual? I bet it will show this system. Your local library may have a Chilton or Haynes in the non fiction section. If it doesn't cover your model look for a similar set up in a Ford Ranger of the same vintage.
Anyways, do a cleaning job and look for vacuum leaks.

 

What you have circled is the choke adjustment. Is the carb loose at the base? That diaphram to the right with the vacuum hose on it is the choke pull off. That acts kinda like the carb base gasket might be sucking air. The hold down bolts are usually around 14-15 inch pounds, so not much. I'd suggest check them, and replace the vacuum hose's. Is that thing you are holding from a vacuum source?