Golf turbo help. PLEASE !!!!

[golf 4]

Please someone help me. I own a 98 Golf Gti Turbo. The problem is sometimes when i drive i put my foot on the accelerator and the car hesitates to pull then suddenly goes. Also when i break the idle drops right down and the car nearly stalls. Also my spark plugs get dirty very quickly and there is a smell of unburnt fuel when i drive. Maybe running rich? Iv replaced the MAF sensor, air temp sensor, cleaned the plugs, cleaned the throttle body and fitted a new dump valve. Yet the problem still occurs. Any help will be much appreciated. Thankyou

[golf 4]

Thanks for the suggestion. How much for coil packs? can i easily diy fit them?

[golf 4]

Thanks for your help everyone. Im going to get the car on the ramps tomorrow on look over all these things. Will let you know how i get on