BroncoII4x4.com

I just started having this problem. When my rig gets heated up it misses or hesitates big time when I step on the gas. Only when its warm does it do this (runs great when cold) Any ideas as to what it might be???

2.8L or 2.9L?

if it's an 86 or newer:

coolent temp sensor

but pull codes first just to make sure.

its an 86 2.9 auto.

Could be the TFI module on the side of the distributor, or possibly the coil.

yeah, those would be a good starting place also.

well if it seems like tis running out fo gas it could also be the in tank fuel pump. mine always died when it got hot then if you let it sit for 15min it would work again for like 4 hours

i got a 1988 2.9 it was doing the same thing i ran some STP Fuel Injector Cleaner through it and it runs better also run sone STP oil treatment hope it helps!!

I read somewhere it might be the 02 sensor, so I will be replacing that today along with both cat converters.

did you pull codes?

if you didn't pull codes you are pretty much shooting in the dark.

codes don't seem to do anythin for me. sounds like the o2 sensor. my 2.9 did the same thing. u can run for a while and when u start to stop and then accelerate again it messes up right? make sure if u put a new o2 sensor on that u leave the battery unhooked for a couple hours to reset the computer. this will erase the old data about the old o2 sensor. hook up your battery and take it somewher where no one is. fly like hell to 55 and gradually stop. wait 10 seconds. accelerate normally to 55 then gradually stop again. then granny to 55 and gradually stop. this should set it for the most part. it'll prolly be about 300 miles b4 its completly at its best.

well what ever it was worked cuz when i brought that bad boy home 250+ miles it road good. damn i miss hp.. lol

I am having the same problem with an 88 2.9, I also think it could be the MAP or BP sensor (I don't know which one the BII has) because it also controls the fuel ratio.
The problem I am having makes it dump fuel and put out tons of black smoke when warm.
The bat has been disconnected for months and I don't know the history so I am unsure. I think I will start swapping out spare sensors to see what fixes it starting with the O2, then the MAP then the temp and ACT.

Put a timing light on it and watch what the timing is doing at different RPM. One BII I had wouldn't advance. It turned out to be a bad computer.

Not saying that's your problem, but it's something to check.

i know theres a way to check some of the sensors with a multimeter. check out www.fordfuelinjection.com it's a good sight on understanding the job of the sensors in your rig.