2001 Blazer 4WD 4DR 4.3L "W"

Sometimes my transmission kicks for no reason. It only happens one day a month or every other month. It will happen most notably while driving on the highway, but happens on city streets as well. It doesn't matter if the engine is hot or cold. I can be maintaining a constant speed and it suddenly kicks. I'm not sure if it's slipping in and out of gear or what. The car kind of jerks real quick.

The fact that it happens so sporadically really throws me off. It will do it throughout the day, and then not again for anther month ortwo. I've had the transmission flushed, and the transmission fluid is full. Does anyone have any idea what the problem is?? PLEASE HELP

 

Do you see the rpms jump on the tachometer?

Possibly could be a very random misfire that causes the stumble... It may not be a transmission problem at all. It may be happening at other random times that are not as noticeable as well.

When was the last time you did a tune up (plugs, wires, cap & rotor)?

 

I'm pretty sure the tachometer doesn't jump, but I'll make sure and pay closer attention the next time it happens. I just did a tuneup around 12-15K miles ago. Put in new plugs, wires, rotor, etc. Just this last week I had the fuel injectors cleaned. (where they unhook the fuel line and run a cleaner through) It hasn't kicked in a couple of weeks. Do you think it could have been the fuel injectors? I definitely noticed a difference afterwards. The engine runs a lot smoother, but it wasn't terrible before either. I guess I'll find out if it doesn't kick for a few months.

 

I have experienced something similar to what OKC described. Happens randomly. I have noticed it happening around 50 mph, when it does happen, which makes me think it is something with the transmission between 3rd and 4th gears. It happened most recently, right after a filled the tank, again at around 50 mph.

Any ideas? Mine is at 218,000, but I am easy on my transmission, plus I have had the fluid and filter changed on it 2-3 times in its lifetime, most recently about a month ago.

Thank you.

 

Same question applies: When is the last time the truck had a tune up?

 

My last tune-up was within the last 5,000 to 10,000 miles.