I noticed this weekend a wierd surging that has never been present before. When the truck gets up to speed, I push in the clutch and apply the brakes is the only time it happens. It does not do it (that I can tell) if I only push the clutch in. It's not warped rotors catching the brake pads, because it continues to surge briefly after comming to a full stop. I recently have had the throttle body off for a cleaning. Replaced the gasket, with no vac. leaks. Could it be somthing on the TB sticking? I did a search through the boards but found nothing that matches my problem.

2.3L '94 manual 5 spd.

 

Sounds like your booster is leaking or maybe a bad BOO switch. Does it do it while you're sitting still? Unhook the vacuum to the booster and see if it still does.

 

Nope. It doesn't do it when sitting still. After comming to a complete stop it will surge once or twice, then it idles normal. I'm not quite sure what you mean by booster since my engine is still stock. Thanks though, got any other ideas??

 

I think he means the brake booster.

Is there any hissing from inside the truck (windows up, A/C and fan off, radio off)?

Do the brakes feel mushy or do they pulse as well?

After saing the TB was off, I would also guess a vac leak or maybe a hose.

 

The brakes feel like they always have and they don't pulse, that's how I know it's not warped rotors. I haven't noticed any hissing but will check later ( I drove the car today). As for the TB... I had that off a month ago and this surging only started this weekend. Could it be a clogged PCV valve or perhaps the TB springs need to be lubed??

 

where is the Booster located? Could it be the check valve to the booster?

 

The booster is just behind the master cylinder.

 

Thanks! Maybe I'll get time to look into it this weekend.

 

It turns out that it was the throttle idle adjuster screw. It was turned in too far and the engine was idling at a very high RPM. (don't have a tach.) So the throttle sensor could not compensate enough when I let off the gas. I backed out the screw enough to lower the idle speed but not stall it out. Problem went away. Thanks for the suggestions and help guys.

 

My truck sometimes does the complete opposite. When i apply the brake the rmps decrease and feels like it is about to stall. Like i said, this only happens sometimes. What could be the cause of this? Its not really a big problem. My engine hasnt stalled yet and it doesnt seam like its getting worse. Just curious.

 

Yeah, somtimes when i go to a stop, it will surge, not all the time, just sometimes, what is with that? it idels at about 600-700 rpms warm, (I have tach), otherwise about 1000 or 1100 when cold

 

Bassaway & Peter94,

You may want to check into getting a code reader from Walmart or some place. I used mine to help locate the problem. I was throwing a code error for the EGR valve. But that was due to the amount of vaccum passing through it from the high idle. However a bad or clogged EGR valve will cause your vehicle to stall when decelerating or when RPMs drop.

 

Note: 94 Rangers with the 4.0 do not have an EGR system unless they were originally sold in Californianland.

 

Yeah, no egr here, i've heard it might be somthing to do with the idle air control valve, and i have a code reader from wally world that flashes an all clear