I got an excursion limited and I recently replaced the injectors, replaced fuel filter. Has a hard time starting but when at idle it runs somewhat smooth until I give it gas then it chokes or sputters at 1900-2000 rpm and won't get any higher, while giving it gas and tops out there's a lot of white smoke coming out the pipe. I tried driving it and it acts like it's not shifting and top speed is 25. Please help I've tried everywhere.