GM-GMC: no power when cold, mass air flow sensor, mass air flow

Question
my  1993 2.8 v6 s10 has a hard time starting and does not have enough power to make the truck move until warmed up.  It will lose power when trying to take off when cold. I have change the engine
contol command sensor and idle control valve and fuel filter. Can you please help

Answer
Clayton,

  The fuel filter change was a good place to start....but why the IAC valve and other sensor, is the check engine light on? Or does it come on when it lacks power. Anyways, your problem could be cause by a few things. Testing the actual fuel pressure would be a good place to start, if your truck has a Throttle Body Injection (2 central injectors) then the pressure should be 9-13 Psi, if port injected (1 injector per cyl.)the pressure should be considerably higher probably closer to 30-35 psi. Also a restriction in the exhaust could be causing the problem although less likely if the power is normal after the truck warms up. I would also check the timing and make sure it is within spec. And that it advances as you increase engine speed, I have seen EST(Electronic Spark Timing)Module problems on these trucks, also a worn timing chain could cause fluctuations of the ignition timing. I have also seen Knock sensors on these truck cause similar problems, basicly if the engine "Pings" there is a sensor that "Listens" for ping and will retart the timing. I have seen them fail and ALWAYS sense Ping there for retarding the timing to maximum computer control. The last factor could be a computer control, a sensor keeping the fuel/air mixture too rich or too lean. The major Fuel/air sensors are ECT(electronic coolant temp.)sensor, MAP(manifold absolute pressure) sensor or MAF(mass air flow sensor) and the Oxygen sensor. The oxygen sensor really only starts working after the motor has reached a certain temp, so if only when cold then its probably not the problem. BUT I have seen some "short" to ground and effect computer output all the time(very rare) This gets pretty involved since you'll need a timing light and a means of comunicating with the truck's computer to access the sensor data. It may be a good idea to have a reputable shop take a look, ask around for a shop with a good track record of dealing with engine management problems. If you would like ant more info about testing some of this yourself let me know and we will deal with a specific test at a time! Hope this helps!