I have a 1997 Blazer with 170,000 miles on her. The transmission was replaced about 70,000 miles ago. The engine runs great but lately it seems as if the tranny is crapping out on me again. If I drive any speed higher then 45 mph, the truck has a jerk motion, almost as if she's struggling to drive. It's not a violent motion, but its enough to make me nervous that she'll fail on me soon. What gets me though is that sometimes she'll do it, and other times she won't. When the truck doesn't jerk, the engine is usually cold to moderately warm. Is it possible that it's the tranny or could this be a fuel problem at high speeds? Thank you.

- John

 

quickest way is to throw a fuel pressure tester on the line and check tranny fluid. mine was doing the same problem, and only got worse. Now its to the point to where it will barely shift out of first gear without floring it, it turned out to be the spider injector unit, im doing the SFI to MFI conversion this weekend, but plaease dont take this route without testing fuel pressure first. i hate seeing people throw parts at cars without propper diagnosis.

 

try checking out my post titled "Found my problem!!!!!!" and make sure to read the WHOLE post, it may be the splice pack sp423 which is a ground junction that has the ground for your egr valve that cause this same problem when the ground bolt gets rusted, the fact that sometimes it jerks and sometimes it doesn't means that it may be an electrical problem.

good luck!!

 

I forgot to mention, and it could be important in trying to narrow down what the issue is, that sometimes when the truck is either warm or cold, she'll hesitate when putting it into drive and pulling away. The truck has almost a feeling as if it doesn't quite catch first gear right away, it'll usually take a few seconds and then she's good to drive. Its pretty random when it happens though. Also when backing up when the engine is cold (during 20 to 30 degree weather), she'll give a jerk feeling and almost feel like she's gonna die on me. Hopefully this would help figure out exactly what my issue could be. Thanks for the insight guys.

- John


Alsom, this is the reason why I previously though my tranny is crapping on me.