RPM falls under 400 when braking

[Almoalla6997]

HI there,

The other day I was driving my car around, I came to a road bump and had to brake hard from a speed of almost 60KM/H and let go of the brake at a speed of almost 20KM/H. the engine simply went off.

it happens regularly overtime I brake but the RPM falls to around 300RPM causing the car to jerk, however everything returns to normal once I apply throttle.

Dealer said this might be because of a dirty throttle body the cleaned it but the problem persists.

A couple of tuned sierras don't have the issue because the RPM is raised to 800RPM while idling and when the gear is set to D.

 

please help with your feedback.

 

thank you

[20L8TSierra24]

How many miles are on your truck?

[Almoalla6997]

Around 20000km

[Almoalla6997]

How many miles are on your truck?

Around 20000km and the problem started at 10000Km

[iCryWheniGoPoop]

Sounds like you may need a top side or dry side valve cleaner. Either find a BG service center or use something like this (see link below) and report back with your results.

 

http://www.gm-trucks.com/forums/index.php?/topic/170994-Intake-clean%2E--WOW%21/page__view__findpost__p__1598328

 

 

 

 

 

Sent from Off Driller Side

[ghgmi]

Could it be that you've braked too fast for the tranny to downshift and the torque converter is still locked?

[iCryWheniGoPoop]

Could it be that you've braked too fast for the tranny to downshift and the torque converter is still locked?

That's possible but would just be another issue.

 

Once you completely let off throttle it is programmed to let go of the torque converter at any speed under 14mph for any gear other than 1st, and if in 1st the converter shouldn't be applied at any speed.

 

 

 

Sent from Off Driller Side

[Almoalla6997]

Could it be that you've braked too fast for the tranny to downshift and the torque converter is still locked?

[Almoalla6997]

Doesnt really matter if I brake so fast or so hard it could even happen if i apply the brakes slightly.

MAF sensor is cleaned

Throttle is cleaned

 

Tuned vehicles with raised RPM dont have this issue

 

If you fill up the car with gas while the engine is running rpm will fall and the car would also cut off.