For about the last month and a half I have been having some wierd hesitation issues when I first start my Suburban. When I start it and go to take off it acts like it is not getting gas. After about a minute or less it goes away and seems to run ok. It used to happen only on cold starts, but then it started doing it when I would drive somewhere and it would sit for a few hours. Yesterday noticed the rpms dipping a little from time to time when driving on the freeway. Not super noticeable though. Anyway, last night it did it again and when I got caught in a hail storm I pulled under a gas station cover to wait it out. While sitting there for about 10 min the rpms would dive down to about 200 and it would almost stall. Drove off and the hesitation was back when pulling on to the street. Went away then the SEL light came on. I am gonna get the code pulled later today, but I was wondering what it might be or if anyone has gone through this as well. I drive a 2000 3/4 ton suburban 4wd with a 6.0 and about 171K miles. Only thing I did recently was replace the TPS since it kept throwing a code and the tranny would not upshift automatically on hills from time to time. Let me know.
Thanks

 

I start by checking the fuel pressure, maybe have the injectors cleaned or try running 2-3 bottles of Techron thru a tank of gas....clean the MAF sensor, insure the air filter is clean... check the plugs to see if any are fouled or dirtier then any other....

 

Pulled the code and it was P0122. Tps low voltage. Just replaced it about a month ago. The guy said to clean the IAC above the TPS because than can lead to bad readings. Unplugged the MAF to see if that get the computer to re learn the settings. I will probly clean the MAF but the air filter is brand new. Deffinately need to check the fuel pressure this weekend. I just want to get this sorted out. Its pretty irritating.

 

I have now had the MAF unplugged for 2 days and the hesitation has improved a bunch. Rarely does it. I can however feel the tranny histting the shifts harder into first and second gear. Just curious if that is caused by the MAF being unplugged. I am going to scan it again this weekend, but just looking for more possible suggestions.