What is a speed sensor

When engines are cold, it is usually normal for them to run a little bit rough due to the EGR valve and the timing of the engine with the manifold and components being cold. It takes time to vaporize the fuel to achieve full combustion. The automatic throttle should activate and put the engine at an RPM approximately 1500 to 1800. At this RPM, you should not run the car otherwise you risk losing your transmission in the long run. It may be also wise to tune up your car by checking the spark plugs, the contact points and the timing mechanism. An erratic timing mechanism can give you a rough idle.

Replace the vehicle speed sensor first and see if that cures the problem.

This code reffers to a Mass air flow sensor or(MAF) Check the connections and /or replace it. Good luck.

hi there it sounds like the problem your having is the speed sensor.
before replacing check the wire connection if no broken wires.replace sensor .
the speed sensor is on the transmission.

I'm sorry for your troubles but have they checked for a plugged exhaust pipe after the cats or a plugged fuel filter? I had car in my shop some years ago that did the same thing as yours and it turned out to be a collapsed pipe between the cat and the muffler. some G.M. cars had a double pipe system and the inside pipe would collapse and shut off the exhaust from coming out. Have they disconnected the rear pipe after the cat to see if the engine responds better and changed the fuel filter? If it's fuel injected, did they check the preasure regulator by disconnecting the vacuum hose to it to see if it made the preasure go up? The fuel pump in the tank may not be giving the engine enough fuel preasure any more. Put your hand at the exhaust pipe while its running and see if it feels like its coming out o.k. The sock filter at the tank pick-up may be clogged also. These are things I would have checked before doing all of those expensive repairs that were done when most times it is'nt going to fix it. After almost 20 years, some of the original, never - removed pieces are going to go bad. Like the tank filter and exhaust pipes.
Hope this helps you out,
Craig

Hello csdunne: My name is Roger and I will answer your question. The oxygen sensor will not cause a no start condition. How ever the fuel pump will. You need to test the fuel pressure. Whether you have a 4x4 or 4x2 the pressures are the same. Key on engine off. a 4.3 W engine should have 60-66 psi. A 4.3 X engine will have 55-60 psi. I would also check the fuel filter. A dirty fuel filter will cause low fuel pressure. If the pressure is below the min. by just a few pounds the engine would not start. Should you need further help please just ask. Please rate the answer you received. Thank You for using Fix Ya. Roger

What engine?

The output speed sensor is located on top of the transmission output shaft, this will send speed value to the transmission control module (TCM).
The vehicle speed sensor is installed on the differential of the transmission, and sends speed value to speed gauge on instrument cluster.

Check also IAC valve and look for vacuum leaks using an hand tool gauge(Vacuum Gauge and Fuel Pump Pressure).

Your mechanic is making a wild guess, find out when trouble code is set and go from there.

Check engine light on ? Have it check for DTC'S diagnostic trouble codes . New fuel pump ,new gas cap,because check lite comes., just replacing parts is not the way to fix car's ! Testing the fuel management system ,viewing scan data on a capable scan tool is. Your best bet take it to a qualified repair shop. What are the fuel trims at +- 10% Do you know what short an long term fuel trims are ? The computers ability to control fuel delivery . What's mass air flow sensor data parameters , coolant temp sensor ,are the O2 sensors switching correctly ,
mechanic now thinks it might be in the charcoll pollution canister??? this surging is driving me nuts ???????? You better find a real automotive technician .
007 Idle Speed Problems Scan Data for Idle