motor buck/surge decellerating

[lupey6.5]

i have a '94 blazer 6.5T W/4l80e trans.for the last few months it seems that when i am decellerating from highway speeds as soon as i touch the brake the motor seems to buck/surge a couple of times. it also does that thing where you first put it in gear sometimes and it surges just for a fraction of a second. i'm thinking it has something to do with the trans maybe the tcc how do i track it down?

[Crashwesson]

That sounds similar to my 94'k3500 See the Newbee needs to know. It only happens when I let off the pedal. I hope there is someone out there who dosen't think we are nuts

[jspringator]

Mine was the PMD. Only happaned once {recently}since then. Probably going out again

[lupey6.5]

mine is not when i let off the pedal but when i touch the brake and i guess the tcc lets go

[CareyWeber]

My 97 kinda doing the same thing 160K miles; sometime it does it almost a complete stop and causes the truck to lunge forward.

I'm going to add a relay to provide good power to pin E (search for 4L80E pin E for more info) on the trany connector.

I think its probably in the long run going to require a new torque converter however.

Carey

[kowsoc]

I have a 94 and my Dad has a 96 and they both have always done this. Mine is when slowing on the highway and touch the brake the engine gives a couple short bursts then idles normally. Occasionally I also get this when just putting the truck in reverse. A dealer I talked to said they're fully aware of this problem but it has never been a real safety threat. I know someones going to jump in and say it is the IP going out but I've put 100,000 kms on my truck and the problem is just there....doesn't get worse...doesn't get better. My Dad's put about 150,000 km's...same story. FSD's are both on coolers and new one's might have decreased the occurance of this a little....not sure. The surge does not occur very often and seems to happen when the engine is good and hot. Using PowerService Diesel Kleen seems to help somewhat. We've been just living with the problem and probably will continue to do so unless it starts to get worse. smile.gif

[Paul Amestoy]

Well that happened to me a couple of years ago and when I tapped the brake it would also change my Tach and push the needle up a few K.... I finally had enough and the dealer could not fix it...so I started looking at grounds.... I found that the ground behind the glove box ( where the computer is ) was not a proper ground.. I pulled a solid ground from the battery to that post and voila.... it fixed it... and my radio worked better.... James let me know why you are using a number 9 resistor.... you have about the same set up as mine... I have a 1998 K2500 Burb but only the remote fds... I am thinking of a 31/2" exhaust... have you done this mod?