Well the body on this bronco is absolutely amazing and everything runs perfect and whatnot, except two things.

1. When i come to a complete stop and step on the gas, the bronco seems to like jolt a little bit, almost like the engine misses, could that be the case? Should i change the spark plugs? I have no idea if they were replaced before and it has 105k miles on it.

2. If it is missing , would that explain the poor acceleration? Now i know its an SUV , but i had an 86 5.0 Stang, that was stock and it had some giddy up.

 

bump? anyone?

 

What year Bronco are we dealing with? Which engine?

 

What year? What engine? What mods? We need a lot more info before anyone is going to try and figure it out for you.

 

Is it a true miss or a jerk type feeling. My '93 had a jerk to the takeoffs when I bought it. I found the slip joint on the rear drive shaft was not "slipping" with the body shift of accelerating. Pulled it apart and greased things and it is much smoother now.

 

Its a 93 with the 5.0L all stock. And it kinda jerks, but when i gently press the gas its completely fine

 

Your best bet is to pull Codes and see what the truck "says" is wrong with it. You could be chasing any number of potential causes. The Codes will pinpoint specific items. A Code reader costs about $20 at most parts stores but most parts stores will pull the Codes for free for you. There is a "home made" method of pulling Codes but it take a little practice to be accurate about it. If you have someone pull them for you INSIST that they tell you the actual Code numbers. Often parts stores will just tell you what the Code might mean and try to sell you parts accordingly. DON'T DO IT. I've seen parts counter guys throw $200 worth of parts at someone to "fix" a particular Code when it was only ONE part that would have been necessary.

You can try cleaning the throttle body and the IAC (Idle Air Control) valve assembly (mounted to the side of the throttle body) but if there are any fault Codes associated with this issue that won't necessarily help the problem.

Third, you might want to check base timing as well. Tip-in response can be sluggish if base timing is off. The procedure fro checking/setting base timing is on the under-hood "CATALYST" decal. Make absolutely certain that you warm the engine to operating temperature BEFORE attempting to check/set timing.

 

Most parts stores around here do not have the old style equipment to pull the codes on '93 and older. They only have the OBDII system. Real helpful of them... The code reader is a breeze to use and the home grown method using the dash light is pretty easy too.

 

Getting a code reader is definitely worth it. And like others are saying, you don't want to start throwing parts at the truck because you may end up wasting money.

However..... I would change the spark plugs if you don't know when they have been changed. Spark plugs are fairly cheap and pretty easy to replace. I had a slight jerking/stumbling at lower RPM unless I very lightly hit the gas. After changing my spark plugs, it went away. Just gap them to .55 and get the standard copper motorcraft ones. It's worth it in my opinion because its part of normal maintenance, and its better to change things too early then too late.