Ok, Im really stumped on this one. I have a 1993 K-Blazer (350 235K) and I was having a problem where I was unable to start the truck without pumping the gas pedal. Not normal behavior for TBI! As well, it would often stall out when I was coming to a stop. However, once you would get into thegas pedal it would run perfectly and maintain RPMs at all speeds except coming to stop and would shift perfectly with no hard shifts. This problem would improve slightly at operating temp, but still it would want to stall coming to a stop, and I would need to pump the gas to get it to start when first starting the truck, hot or cold. I have recently replaced fuel pump, fuel filter, and IAC so these are not causing the issue. I have checked all vacuum lines and sprayed carb and choke cleaner all around the intake/TBI trying to locate a leak while the truck is cold, but no luck. Tried replacing the TPS and that didnt fix it, in fact replacing the TPS gave me a code 22. Weird. Anyhow, just now it started "starting" normally again out of the blue, just like old times. However, then I would bang through the gears once (1-2-3-4, etc) and the next time I would come to a stop, it would no longer drop back down to first. I noticed the shift from first to second was abnormally hard. In addition, I lose OD too! So, in short, I went from running poorly at startup and stalling out, but shifting perfectly, then when it starts to run perfectly at startup, I lose 1st and OD. If I disconnect the battery to get it out of Limp Mode, it will run fine at startup and bang through the gears fine only one time (with hard 1-2 shift). Then, next time I come to a stop, I lose 1st and OD again. No "Check Engine" lights before or after being forced in to Limp Mode. In addition, before and after I lost 1st and OD, when you give the truck just the slightest amount of gas (eg. maintaining highway speed on a flat surface), it sort of bucks and runs rough. Ive been reading posts on here and Im ready to change the MAP sensor next.Think Im on the right track? I want to post this in case anyone else is experiencing the same problem and I am able to fix it.

 

I just replaced the MAP sensor and there was no change. Still have a hard shift form 1st to 2nd, losing 1st and OD thereafter. Truck still starts perfectly now though. Anyone have any insight? I almost wish that it would run badly at idle again so I could get 1st and OD back!! I don't know what to replace next. Please help!

 

Could be two problems where one went away (bad gas maybe on the hard starting/stalling issue) and the other one presented itself. Both could be (have been) electrical problems (check over all of your wiring). The transmission problem could be caused by sediment, a poor electrical connection, or a bad seal in/at/on the 1-2 shift solenoid.

 

Thanks for the response Kyle. I appreciate it. Let me elaborate about the vehicle in case it helps at all. Tranny was rebuilt about 25K ago. I was driving it daily when first the shifting problem started, then the hard starting/stalling became a problem. I got fed up and parked the car last winter and bought another winter vehicle. That vehicle stopped starting the other day, so I tried out the Blazer because I knew at the very least that it could get me where I needed to go. I was pleasantly surprised to find that the shifting was perfect for about 3 or 4 days after having no battery in it for a year.No hard shifting or loss of 1st/OD. I mean perfect. So I set about tackling the hard starting issue. Couldn't fix it. Drove somewhere, parked it. When I started the vehicle again, it fired right up smooth as could be, but I immediately lost 1st and OD. This is what made me think that they are related. I will give the electrical the once over, but I have a hard time figuring out how the hard starting "fixed itself" when it became a problem while it was a daily driver and I did nothing to fix it. Hard starting persisted for the year it was parked and for 3-4 days of new gas, then literally disappeared between parking, going to the gym for an hour, then starting again. Soooo weird. I'm at my wit's end on this one.