This weekend I did a tranny fluid/filter change. Everything was running fine beforehand just some preventive maintenance. I did not touch anything else. Anyway, now when accelerating from a stop it wants to hesitate. It doesn't rev high or anything just noticeably sluggish. It only does it when first taking off and as soon as you get going it runs as normal. This never happened until now. Did I do something wrong? Is this even tranny related? Any input would be much appreciated.

 

Im not an expert but its possible that you could have damaged a shift solenoid when removing or reinstalling the pan, they are real close to the pan rail, or possibly a pinched solenoid wire, the question is, is it really acting normal? Can you watch the tach while accelerating to 55 from a dead stop and verify that its actually shifting through all 4 gears? If its feeling sluggish also try selecting manual 1st/low gear and see how it acts? Also, any check engine light or codes? One last stupid but possible thing, did you set the e-brake when you had it jacked up to drop the pan? Its possible the brakes or cable are hung up making it feel sluggish, sometimes its the simple things?

 

Is it an engine related hesitation, or in the transmission? Does it idle fine, and rev smoothly in neutral? Maybe you accidentally pulled a vacuum line loose working on the transmission, and now it's running rough?

Also, like DimeBlazr said, manually shift the transmission and see if there's any difference.

 

I had the engine replaced in this truck and i get it back, the exact same problem i had before is still happening. when i acceleration, its a hard hesitation and today i was at the gas station, i turned my car off and turned it back on and it died while it was on and i did it again and it started right up plus i smell burning oil seems like. i think its bad sensors or they where put in poorly. its a 99 blazer! help me! and the check engine light is on. my tranny kinda kicks going into drive and it very poorly driving like a lack of engine power!

 

The start and stall thing could point to a fuel related problem, you may be getting "Key ON Fuel Pump Prime" but the fuel pump relay isnt staying on or making good contact and sending low power to the pump causing lack of power. Try swapping your fuel pump relay with another relay in the under hood fuse panel.

On the oil burning smell, ive had a condition twice with these 4x4 set ups where the rear seal in the transmission leaks which overfills the transfer case, the transfer case vacuum switch then allows transfer case fluid to be sucked up the vacuum hose into the front diff actuator or the vacuum reservoir and then when you start the engine it sucks the oil through the vacuum hose to the intake and is sent into the engine and burned, it really stinks. This could also plug up the catalytic converter real quick so the reduced power could be caused by that, or the transmission is very low and youre having a lack of fluid situation and burning it up.

Both of these "Hesitation" problems have pretty vague symptoms listed, until I know more i'm pretty much shooting in the dark.

Things that would help:
Is the Service Engine Light on? (Get codes if it is, Helps Big Time, most auto parts stores will check them for you, write them down and post here)

How does the engine run in park? Does it rev freely and sound snappy if you give it quick full throttle taps? If it sounds sluggish you may be looking at exhaust restriction or fuel pressure problems or at least we can narrow it down to being engine related.

Does the vehicle roll freely in neutral (Brakes not binding)

Transmission fluid level and condition (Hot idling in park must read full, funny things can happen if its just a half inch below that mark) Also if you have the trans to t-case leak I was talking about above, it can be low but you have never seen a drop on the ground.

Sorry for the long post, if you can get those check engine light codes and provide some more info I will be glad to help further.

Good luck!

 

Its more of a pull when its starts accerating, like a pull/stop stop thing like its trying to get fuel to the motor but cant. then it smooths out after about 40 to 50 seconds. I know if i kept it running for a peorid of time it will prolly cut off. my mom said she saw oil dripping but i checked it and it was full. it decreases speed sometimes while driving. its hard to get to 60

 

Thanks for your input guys. The hesitation is only in first gear. I manually shifted and 1st is the only gear this happens in, no problems in neutral. I don't think it's the brakes binding because it rolls at an idle while in gear. It's just when you initially accelerate in 1st, once you get going a little bit the upper end of 1st works fine as well as every other gear. Just lower 1st feels like there is a lot less power than there should be. The tach shows normal RPM range when this occurs too. Maybe I should drop the pan again and have a look see. I also thought of the fuel pump issues but the timing seems almost too coincidental.

 

Ok so after driving it for a few days here is an update. There is no problem until the engine is warmed up. When I leave in the morning it takes off just fine until the engine is fully warmed up then it starts in again. I also noticed that the fuel mileage is noticeably better. During a normal week I would normally had to fuel up by now, but I still have a quarter tank left as of tonight. This is a welcome change but may not be a good thing. Also the check engine light hasn't come on at all. Hope this helps. Thanks.