Mechanics

S10 ENGINE SURGE/HESITATION-HARD SHIFT OR NO SHIFT!

2010 Chevrolet Blazer

First off, Chevrolet S10 Blazer, 4.3L V6 automatic with a measley 206,000 miles! She was running great up until about 6-7 months ago.

Problem: Upon slow acceleration, at any speed, the engine will drag and hesitate. The Service engine light will come on and then the car will not want to downshift or shift at all. When floored at this point, nothing happens. Acceleration is virtually zero. After stopping the car (say at a redlight), starting again it will refuse to shift into 2nd gear. When it finally does, it will make a hard " thunk" sound and the car will surge forward. If the car is stopped and turned off for awhile, everything seems to go back to normal. Faster acceleration keeps the problem at bay. Having the heat on will make the problem happen pretty quickly so I run without it (I layer up well).
Transmission fluid and filter have been replaced recently, as well as, the fuel filter, fuel system cleaning, oil and filter. The speedometer also sticks and jumps as well on longer drives but I haven't checked the other posts for that yet!
Long and drawn out but that's the best I can explain it. Thanks for any posts you can direct me to that I may have missed or advice.
Avatar
IUReis
February 8, 2007.



Disconnect the TCC solenoid on the tranny and road test again to duplicate the problem.

Rasmataz
Feb 9, 2007.
Sounds like you might have gotten your moneys worth out of that trans. Have it scanned for codes. Usually when those trannies start having 2nd gear shift problems it time for a rebuild. There were a ton of updates to the valve body in those that pertain to hard/late 2nd gear shifts. Have it scanned first, get back to us and we can go from there. BTW what year Blazer?

Tiny
Jack42
Feb 9, 2007.
The ol' S10 ran fine today, of course. Yesterday, though, after being driven and doing it's usual surge, etc. I put it in park, idled for a sec and then put her back into gear. Wham. Really was quite a jolt and then the same shifting hard into 2nd. Again, though after resting awhile, it was great. FYI.

I'll check the codes again and see what I can find this time. Always runs great when it's being checked! Thanks rasmataz and 2CarPro Jack. I'll get back to you on what I come up with.
BTW, it's a 1994 S10. Thanks.

Tiny
IUReis
Feb 9, 2007.
Finally found a code checker for the S10! The code checker (Actron CP 9001) displays Code #22. The description given in the manual was. Throttle position sensor (TPS) signal voltage is low during engine idle OR Fuel cutoff relay circuit is open or shorted to ground.
Does this make any sense for the shudder problem? And how does that connect with the hard shift problem when the Check Engine light comes on? Thanks again.

Tiny
IUReis
Mar 5, 2007.
The throttle position sensor is like your throttle valve operated by vacuum with the old type tranny.

The VSS vehicle speed sensor is the governor

Rasmataz
Mar 5, 2007.
The Throttle Position Sensor tell the ECM how much throttle you are giving it. There is a link at the bottom of main forum page for Auto Repair Manuals. Go there and you will find all specs and instructions to test your TPS

Tiny
Jack42
Mar 6, 2007.