Team, let see if y'all can help me figure this out.
1999 4wd 4.3 4 door blazer...

This is a long story but it is all tied up so bear with me.
About 2008 or so this truck started to have problems with the injectors. I will get codes P0171 and P0174. I changed fuel pump, fuel pressure regulator for new oem parts. I drove and haul my camper with that lean issue for until about 2013 when I finally changed the injectors and it cured the problem, MPG went up, car will not heat up any longer when hauling up in the mountains and instead of not being able to do over 15 mph on the hills now I could do 45 easily. However, being all this time driving lean must have burned the valves. Motor has never been back to normal.

A few months back I saw some smoke in my rear view mirror, not much, it looked as if I was burning oil so I figure it is the valve seals. When I get to my destination I get the smell of burned powder. I look under the hood and on the passenger side there is a wire harness burned, all wires exposed, upon further inspection I can see that the hose from the secondary air injection pump check valve on the passenger side is burned also together with 2 small vacuum hoses(4wd hose and I have no idea where the other one goes). I then realize the check valve failed and all that hot air melted and burnt all the wires insulation.

I limped back home, about 15 miles, the last 1/2 mile the blazer is buckling, rmp gauge is going crazy from 0 to max and I can barely go up a tiny incline into the neighborhood. I fixed the wires with 3m black tape, replace the check valve but now the car will have issues accelerating and it is throwing a MAF code. I will have to check it again as I forgot to write the code down but will update this thread with it...

Anyway, I did change the maf with a good known maf I had from the time I was trying to figure out the lean codes, the car does not do any better and still get the same code. I figure the catalytic converter got plugged and blew up that check valve so I cut it off... still no help and I am getting the cat code too, which I can fix, not worry about that now.
This is how the vehicle behaves..

Crank it to warm it up, it is very rough and the motor vibrates quite a bit for a few minutes until it is warm. I get in the car and it takes a lot longer to shift to 2nd gear, car does not seems to have strength, when it tries to go into 3rd gear it start bucking so I ether step on it, it will downshift and once I get real speed I can let it go to third OR I ease up my feet off the gas a little and hope to gain speed but it will buck just not a much or often. If I ever make it to 4th gear and it is flat it gets speed up to 60's but It does really dont want to do over 45.

Unless something shorted and damaged the computer I have no idea what to look at next. I dont want to dump a bunch of money in this car. I do have a new vehicle but I need an suv for my daily and for deer season. I love to hear where to start with a good educated guess.

I have torque app so I can ride the car and look at some of the motor numbers and have quite a collection of tools and testers, I have always done my own mechanic but this one i have no idea where to go other than a rebuilt motor/transmission...

Also, where will that other vacuum hose go?, it crosses close to the check valve on the passenger side, that is why it burned. It is not the 4wd actuator vacuum hose.

Thanks y'all!

 

Wow, lot going on. My sincere sympathies. There are two places I think you should start. First, have you ever changed the motor and tranny mounts? The vibrating engine part makes me ask that question. The stock mounts are crap and it is very common for those to go. Of course I can't personally witness how much or little it is vibrating. I see that as first major concern so that you do not damage any major drive train components. The other first step is I would start with a clean slate and attack codes as they pop up. Download the GM drive cycle test. Clear your codes find as empty as a road as you can and perform the test. The test will check every sensor in the truck under actual conditions and it only takes about 20 minutes or so. Then, because I assume some DTCs will be set, post all the data on this thread that the first code that pops up shows. There are some very sharp folks on here that can take all that info and point to the most likely issue to repair on that first code (myself not necessarily included, but I'll tell you when I know and when I'm speculating). Personally, after that I would start over again after the fix by clearing the codes and doing the test again. One problem often causes some of the other ones, so just running down the list of codes and doing repairs may be unnecessary on some of the DTCs.

EDIT: Also, I think I can help you with the vacuum lines but I can't visualize exactly the spot you're referring to. Can you post a pic?

 

Sorry for my delay, it's been crazy. I made a note to make sure I dont forget and check the codes and the vacuum line tomorrow.
Thanks!

 

 

too much, too little?