2002 Kia Sportage acting sluggish and more

[REP2008]

Any help would be greatly appreciated. Recently our 2002 sportage has been really sluggish, hard to start and the engine light goes on and off. It
The problem started about 2 weeks ago, it got sluggish and has gotten worse. now it takes for every to get up to speed.
Also it has been having trouble starting at random times. When it does not start if you pump the peddle to give it more gas she starts up and is ok after it warms up a sec or two.
Thought it was the cat converter but took it to a local shop and they said it was not that and recommended the dealer.
In regards to the check engine light have gotten a knock sensor code, a heater fan realy code, and a temp sensor before today. When the local garage I brought it to hooked it up they got new codes. They got the knock sensor and two manufactures codes regarding fuel. The light does go off after a little bit.

So with out wanting to spend the 100 dollars the dealer wants to tell me what is wrong with it. Can someone please give me ideas to fix or check.

I have unplugged the mass air flow sensor because the dealership said that might be bad and that made the car not run at all.

Thanks

[danvhp]

If you have alot of miles on it. The timing belt may have jumped a tooth and now the timing is off. This can cause sluggish performance and all kinds of odd codes from the ECU.