The problem start about 4 months ago. The problem is my 2000 chevy blazer is started and put into drive. I will depress the gas and will get going. To a point.... At 15 to 20 mph the blazer will start to sputer and remain at that speed. Then I will slow down quickly or slowly (doesn't matter how fast) and depress the gas again it will run fine. The only other time I will have a problem is when I fully accelerate the sputering will slightly come back and wont shift very easily. I have replaced the fuel filter and did a fuel cleaner already. I am looking for any one who might have a answer to this.