Hesitation during acceleration and low rpms at cold startup

[1996k1500]

This topic is all too often heard but I can't find out the problem with my truck and I dont want to go about spending money that I didnt need to.
Now the problem:

About 4 months ago when I started the truck cold, it would idle around 1500-1600 rpms. And from that time to now it went down to 1000-1100 rpms cold.
When idling the engine would almost miss and the rpms would drop to 450-500 rpms then raise to 800 rpms and then back down to about 650. This would happen about 6 to 8 times a minute.
During acceleration: if it is a VERY slow acceleration, nothing happens and it runs fine. But if I drive it like I normally do it will shudder for a split second (Shaking the engine and the truck) and then run fine. after about 800rpms.

this ONLY happens when the truck is warm. When it is cold, it runs like a champ.

and my mileage took a HUGE dip when I changed the plugs. I went from (the day I bought it) about 14 city. to about (4 to 6 months ago) 10mpg. and that of today where it is stupid. I can get about MAYBE 100 miles to half a tank.

Now here is the funky part; If I drive it nicely that crap happens. But If I drive it like its stolen it runs just about perfect at idle and acceleration.

What the heck could this be? I'll see if I can post a video or something cause this is annoying and I want to start driving my baby again. I hate my malibu.

 

[1996k1500]

And when i am cruising it drives fine and runs fine.

 

[92GMC]

How's olds the fuel filter, rotor cap and button?

 

[1996k1500]

Fuel filter I would say is about 5 months old. Around that time frame anyway.
And I havent checked that yet. Those may be a bit older. Say around a few years. I will have to check.
Button? I haven't heard that term used before. What is that?

 

[92GMC]

Sorry had a few too many beers lol. Dizzy cap and rotor button. If any corrosion, replace with ones with brass terminals.

 

[94Sierra4x4]

Same problem here....

If trucks at operating temp, and I turn it OFF then back ON. It will drive like a dream. Wait a few minutes, and it'll jerk sputter and such when you try to drive 'nicely'

Drive like you stole it.. and she'll perform like a brand new machine.

 

[1996k1500]

I'll take a look at ignition parts and replace them if I need to. But otherwise I guess I'll dive it like I stole it. Its more fun anyways