Serious Hesitation Problem

bones101 · Post by **bones101** » Thu Feb 15, 2007 4:26 pm

Hey guys, when I'm accelerating in my Bronco II I experience a very serious inconsistentency in my power - which ruins my ability to accelerate quickly.

It goes a little like this; when I put my foot down on the gas, it starts to thrash back and forth. One second I'm accelerating, one second I'm not. Which makes for a really rough ride, and a scary experience trying to merge onto the Highway, or beat some on-coming traffic... Ya know? I think it's some kind of hesitation, but I don't know whats causing it.

Fuel pump? Fuel filter? I really believe it has something to do with my fuel system. The injector is where my bet lies. But, what do you guys think?

Any suggestions as to what I should check, am I lucky enough to have found a group that has people that experienced the same problem? If anyone has, let me know what it was so I can get it fixed!

Thanks everyone;

~James

HERE IS MY TRUCK......

Post by **Nobody** » Thu Feb 15, 2007 4:32 pm

I would lean toward the TFI module on the distributor. Bad spark plug wires can also cause this.

BDEUCE · Post by **BDEUCE** » Thu Feb 15, 2007 5:23 pm

don't write it off as fuel yet - like limited says, no point throwing parts at a problem to try and figure out what it is.

suggestion 1
try the search feature on the main forum page. use all keywords applicable.

you really need to supply us with more info, ie - i guess you might have a 2.9 because you said injector? btw, there are six injectors, and are not cheap.

suggestion 2
if you have a distributer, often hairline cracks form where the wires stick on, and it is possible to lose an arc to some metal or something. check spark first - wires, plugs, cap & rotor. these are the cheap things if you want to just change them anyway.

Suggestion 3
check fuel pressure. i don't know how, but search the site to find out how.

is it possible you got bad gas? change fuel filter. is it an auto? because auto's can host driveablilty problems. do you notice missing or smoke or clunking, clicking, grinding, backfiring, sputtering, coughing? you really need to give us more info, because it could be a cap & rotor, or your heads could be cracked, or your rings are toast. any check engine light?

i also hope you will become a full-time member after we help you too!!

Nate

bones101 · Post by **bones101** » Thu Feb 15, 2007 7:06 pm

Well here is the info..

It is a 1986 2.9 EFI V6. The only weird sound that it makes is when I down shift it will have small backfire noises. When I was first trying to get a feel for what was going on, I tried accelerating, knowing it wouldn't accelerate smoothly. When it bogged down, I threw it in Neutral and tried to rev the RPMs. But the Needle didn't pop up... They would stay the same as if there was something blocking the fuel from getting to the Engine, ya know? But I will take a look into your guys' other suggestions. Thanks.

Post by **Nobody** » Thu Feb 15, 2007 7:18 pm

BDEUCE wrote:is it possible you got bad gas?

Good suggestion. I've had a few tanks of bad gas that caused problems like this.

BDEUCE · Post by **BDEUCE** » Thu Feb 15, 2007 7:19 pm

sounds like it could be a sensor as well. no check engine light? does the check engine light come on in the key on position, before you start it? i ask because my check engine light was burned out when i got it.

how does it idle, smooth or erratic up / down? does it seem to run kind of rich? how's your fuel economy? it almost sounds like a map sensor now that i think about it.

you got me thinking, anyway.

Nate
Check this out:
http://forum.broncoii4x4.com/viewtopic. ... hlight=map

Bronco Buddy · Post by **Bronco Buddy** » Thu Feb 15, 2007 8:10 pm

if it is a standard maybe its your shifting, im not trying to slam you or anything i had the same problem with mine it being my first standard vehical.

Phillippi · Post by **Phillippi** » Thu Feb 15, 2007 9:21 pm

Dont forget a possible cat clog.

Post by **Nobody** » Thu Feb 15, 2007 10:07 pm

BDEUCE wrote: Check this out:
http://forum.broncoii4x4.com/viewtopic. ... hlight=map

Damn, I'm always wrong

Hair · Post by **Hair** » Fri Feb 16, 2007 6:46 am

I had the same problem with mine!

turned out to be low voltage to the fuel pumps

The fix?

new fuel pump relay!

BDEUCE · Post by **BDEUCE** » Fri Feb 16, 2007 12:23 pm

are you running 31's in the picture there? i'm looking for new tires,m/t 31-33", but i can't decide.

get out wheeling much?

Nate

baby bronco · Post by **baby bronco** » Fri Feb 16, 2007 12:47 pm

i had the same problem i changed all my wires plugs and distributor cap and the whole nine yards but the problem was my primary filter was completly stopped up jsut about....so i changed both filters on it and that stopped my problem

BDEUCE · Post by **BDEUCE** » Fri Feb 16, 2007 5:16 pm

a fuel pressure check would yield evidence to that problem.

bones101 · Post by **bones101** » Sat Feb 17, 2007 10:40 am

BDEUCE wrote:are you running 31's in the picture there? i'm looking for new tires,m/t 31-33", but i can't decide.

get out wheeling much?

Nate

I got 29's. I want to crop my fenders a little but and put bigger ones on.

But for the rest of you guys! Thanks for the advice, I'm going to check into it. The last time I had a problem like this it was my fuel pump regulator so im going to check out the fuel pump and then the filters. I only have one little problem....when I tried to change that fuel filter on the driver side of my truck, I couldn't get that damn thing off! Any suggestions?

bones101 · Post by **bones101** » Sat Feb 17, 2007 10:47 am

and another thing...

My check engine light does work but its not on. My engine also idles weird when I first start it up, it goes up and down and my gas milealge is TERRIBLE. I'm getting 11-12 mpg. But well see what happens when I try all these ideas out. Thanks again. I'll keep you guys posted.