Transmission shifting hard and TPS light is on

SPUNKIE_ME

MEMBER
1998 CHEVROLET S-10

I have the truck listed above with a 4.3 engine and 144,000 miles. It started out when I am driving it will act just like it wants to downshift, mechanic replaced the fuel filter. Next problem when you start out it acts like it doesn't want to shift at all, when and if it finally does shift, it jerks really hard through the first 3 shifts. Mechanic replaced the TPS sensor, MAP and O2 Sensor also did a transmission flush. Now it's still shifting hard at times the light came on came back to a TPS code have replaced it again but still have the same problem. Also while I am driving it it acts just like I have taken my foot off the gas pedal. My mechanic doesn't know, he had a trans guy look at it and he said the transmission is fine. So this has been going on for a year and 3 mechanics later nobody knows what it is. Any thoughts?

5 Replies

CHRIS1979

MEMBER
7 POSTS

Have you had your converter checked?

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Wednesday, October 31st, 2007 AT 9:23 PM

SPUNKIE_ME

MEMBER
3 POSTS

Supposedly they have checked everything and say that it's something in the motor. They want to do a tune-up on it but are not sure if that will fix the problem or not. What does the converter do? I'm learning as I go along so I don't know about a lot of stuff and it's purpose.

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Thursday, November 1st, 2007 AT 8:44 AM

CHEVY22

MECHANIC
1,375 POSTS

Is it a 4x4?

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Sunday, November 4th, 2007 AT 9:56 AM

SPUNKIE_ME

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3 POSTS

No, it's not a 4x4.

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Tuesday, November 6th, 2007 AT 8:25 AM

KASEKENNY

MECHANIC
18,907 POSTS

Without the specific code I can't provide the testing for it however, the theory of this is the same. The throttle position sensor is used in shift strategy. That means if the throttle sensor is not accurate the shifting will be harsh, erratic, or not shift at all.

So if the TPS code comes back, then this is most likely the cause of the current issue. Unfortunately, it is seen too many times that the code comes up for a sensor and the sensor is replaced over and over, and it doesn't fix it. This is because there are other causes of these codes then just the sensor. While the sensor is the most common cause of a lot of codes, it is not the sole cause. In general there is wiring or control modules as well. As you can see from the attachment there are various TPS codes related to circuit performance. Again this could be the sensor but not only the sensor.

If you can provide the code we can dig deeper in to the cause. However, I am confident that once the TPS code is fixed the harsh shifting will be repaired as well.

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