[wheelMA1]

It only happens once in a while. I will be sitting there (stop light, stop sign, etc), and the truck will try and pulse forward against my braking force. I have been told that it could be my torque convertor going. Then again, my buddy the service manager @ the local Ford dealership said it isnt. Any ideas?


Rich

 

[Cmayer31]

There was a post on Broncos rocking at a stop, but I can't find it right now. Anyhow check to see when it is rocking. Seems like when there is approx. 3/4 a tank of gas the gas will swoosh back and forth in the tank and rock the bronco against the brakes. I've had it happen and it is always right around 3/4 tank full and from the post it seems like it has happened to a number of other people. If it happens all the time then maybe time to look at the tranny/torque converter.

 

[Fireguy50]

trans conveter is doubtfull
try the IAB it might be sticking

 

[Oscar]

when I had my 92 Bronco w/ 302 & E4OD same thing and converter was gone few mounths later at 130.000 miles just bougt new tranny and sold that truck but one more thing to look at what rpm does your truck idle in drive???

 

[wheelMA1]

what rpm does your truck idle in drive???

Youre talking about sitting at a light or something right? I think its right around a grand, maybe a little lower. I mean, its not a huge inconvenience, but I did pay alot of money for this bronco.


Rich

 

[ldj1002]

I had an 89 doing that. I thought it was shifting to low a little after I stopped, causing that lunge or surge. It did that a month or so and quit doing it as sudden as it started. Never knew exactly why it was doing that. Just was glad it went away. I kept it over a year after that and trannie held in there.

 

[origin]

my 88 EFi is doing the similar thing, you can barely feel it, but it is there, it's like a slight surge at idle that can only be felt when at rest, and in gear

 

[TRUCKY18]

my 95 does that, but its very inconsistant, somedays alot some not at all it only has 55,000 miles on it so i hope its not the tranny but i has done it for the 10,000 miles i have owned it, i dont think alot of it any more

 

[Fireguy50]

Everyone with this problem should chdck for comptuer codes to insure there sin't any major problem.
Then unhook the battery for 15 minutes.
While it's unhooked clean your IAB :twak
This will reset the computer and give it a chance to relearn idle controls :thumbup

Good luck to all :beer

 

[Crazyromi]

I wondered about the same problem on my 96 EB. I believe that it is the gas sloshing back and forth as stated earlier. I will only notice it when I have between a half a tank and 3/4. Someone else explained it pretty well before. When you come to a stop the gas will move back and forth in your tank, at 3/4 full thats like 100 or so pounds moving around, causes your truck to rock a little. IMO not something to worry about. Still does it on my truck and the only code I have is "EGR flow insufficient". Check out your gas gauge the next few times you notice it happening.

 

[Cmayer31]

I was wondering if someone would bother to read my post in here. I've searched and searched but can't find the old thread. There were quite a few people having a rocking problem at stop. Majority of them connected the 1/2-3/4 tank condition as the only time it happened. If you experiance this check your fuel gauge..might be part of the problem.