...my truck doesnt like to start when its cold...its a 2001 chevy silverado 2500....when i turn the key i have to hold my foot on the gas and the brake and rev it alot and keep it at 1000 RPM to keep it alive and also to shift and when i slow down or get under 500 RPM it dies...what could cause this?? it also sometimes doesnt start when its warm every once in awhile but when it does it atleast idles...but in the cold it doesnt even idle....ideas!?

Let me 1st say that by no means am i an authority on auto mechanics at any stretch of the imigination but,,,i had this same issue with a ford ranger and a mechanic friend of mine told me to run the truck low on gas,,,,by a can of
BG-44k(this is a gas additive made by BG products) and dump it into the tank,,,then fill the tank with premium (93 octane) gas. I was a bit skeptical at 1st,,,but by the time the tank was half empty,,,the truck was starting and running great,,,and as a matter of fact,,,my throttle response improved and so did my fuel mileage,,,now i do this as part of my preventive maintenance,,,everytime i change the oil,,,i dump a can of this additive in the tank and fill it with premium gas and i hav'nt had any issues since. Supposedly it cleans the injectors and throttle body which causes hard starts and poor response. Hope this works for you.

loose spark plug boot,fuel filter

I was going to say the same, sounds like a major tune up is needed, new plugs wires cap fuel filter, have the injectors cleaned out.

seems how it is a newer truck. It is not your plugs wires etc.. More likely to be a MAF sensor or a Throttle Position Sensor. He is what I would do, drive to you local autozone, they can hook up a diagnostic reader to your truck. Which should tell you what the problem is.

I agree with you on this one, sounds like the mass air flow sensor, or throttle position sensor. Some times you can take the MAF off and spray them with a carb cleaner and put them back on and it will be ok. I know most of them MAF are not cheap. Auto Zone will pull the codes for free and give you a print out of what they find.

I agree with the MAF sensor as a possibility. What engine does it have and is the check engine light on? The mass air flow sensors a lot of times will not set a trouble code/check engine light. The 5.3 and 6.0 liter engines have had problems with intake gaskets leaking vacuum as well. We see more problems cold than hot. When they are cold they leak more and run rough and wont idle well, then when they warm up they expand and seal again. If you have codes read somewhere see what they are and let me know, I can further assist you in the diagnosis. If it has a p0171 and p0174 it is an intake gasket leak. You will probably have p0300 missfire codes also. Let me know if you need more info. You can PM me if you want. Good luck.

Right theres your problem!

You must be a FORD guy?

I believe its either the MAF, OR it could be your IAC Valve AKA: Idle Air Control Valve. It controls your air intake at idle, allowing your engine to consume just the right amount of air to keep it running smoothly.

being that the issue is only happening when you are not giving it gas, I would say almost 100% that it is air intake related, now you just have to figure out which part of the system it is. Not too complicated though.

Read up on the IAC and its location on the web, and see if you can find it on your truck. I imagine its on the bottom side of your throttle body(most are). You can either take it off and try and clean it up a bit, or tap on it lightly to see if you can free it up. Cleaning out your MAF may help as well.

Just try a few of these things BEFORE you go out and spend money on it

Derek