Help Needed ASAP

[ExplorerXLT4x4]

New guy here and need help ASAP, sorry I did not post in the new members section yet, wanted to get some helpful info and the forums seem to always be the best place to get help.

1999 Ford Explorer XLT V8

Mom went away to visit family about an hr away, upon returning from visiting family the explorer started to show resistance at the gas peddle(you could give it gas but it showed resistance in pressing it down further, kept at a steady 50-55 and would not go higher)

When stopped at a traffic light explorer had a pulsating idle(sounding similar to that of a hot rod at idle, sounding like it wanted to die but kept pulsing)

As of now the explorer is in the driveway, when you start it up it has that hot rod idle pulse, when you step on the gas it doesn't throttle forward like normal it pulses forward rather then a smooth movement forward.

Any help before going to the local mechanic would help, especially if its a easy fix that I could do myself.

 

[gmanpaint]

Welcome to the forum!

Sounds like a vacuum leak. Check all the vac lines to make sure none are cracked or broken off. If they all check out, it might be an intake gasket, the DPFE cracked, the vac reserve ball cracked, or anything to do with a vac source.

Worst case scenario is a cracked head , but you would see a loss / leak of antifreeze, and the temps might rise if it's a bad crack.

 

[yavapaires]

Have you ever lubed the throttle and cruise control cable? Try pulling the cables off the throttle body, and see if the throttle plate will open without binding. If this works OK, then look at the throttle pedal pivot. If the throttle plate sticks or shows resistance, try cleaning the throttle body. Hope this gives you a starting point.

 

[LONO100]

if its not a vac leak, you could have a dry throttle cable. like the fella above me say, try running some cable lube down the sheathing. it looks similar to the brake cable on a bike. let us know what happens. good luck!

 

[ERUSH97XLT]

Hello,

Is your check engine light on? Regardless, I would head to your preferred auto parts store with an OBD-II scanner to see if there are any codes.

How's the fuel mileage?

Isn't there a mod somewhere around here for the V8 throttle cable linkage? I wonder if your pedal can only be depressed so far because of a mechanical binding. Does the pedal feel sloppy at first?

Good luck,

ERUSH

 

[gmanpaint]

I fail to see how a bad throttle cable will cause the engine to LOPE.

 

[ERUSH97XLT]

I fail to see how a bad throttle cable will cause the engine to LOPE.

I agree. How can the idle be lopey, like with a high-overlap cam, if your throttle cable is sloppy? Even if it were sloppy, the throttle should remain closed, only allowing the IAC to control the air flow at idle. If the cable was binding the throttle open, your idle would be way too high and you'd clunk into gear.

Start with the basics: air, fuel, spark, compression.

1. Air: check your air filter, clean the MAF, IAC, and IAT, Also wouldn't be a bad idea to hook up a vacuum gauge to see if you can spot a vacuum leak. Do you hear any hissing in the engine bay?

2. Fuel: Check your fuel pressure at the injection manifold. Do you have access to a gauge? A good search around this forum will yield the proper manifold pressures.

3. Ignition: Check your spark plugs, wires, and coil. Do you have acess to a multimeter or an Ohmmeter? All resistance values should be within Ford specifications (again, a quick search around will yield the proper values). To check for arcing, wait until dark, and spray a fine water mist around your wires. The arcing will then be obvious. If you have any Bosch products in your ignition system, those products may be at fault.

4. Compression: This is the least likely fault, but it wouldn't hurt to do a compression test. Do you have access to a compression gauge? I've had similar problems once as well as a slow coolant leak, and it turned out to be a cracked head gasket.

Let us know how it goes.

Good luck,

ERUSH

 

[bobflood]

Simple first thing - look up underneath the dash where the accelerator pedal mounts and make sure the the mounting bracket is still attached at the firewall. Mine broke loose (a well documented issue with these vehicles) and caused very similar problems - especially the physical resistance felt in the pedal.

 

[yavapaires]

My point being: fix the obvious FIRST. Then address the other problem. Find out why the pedal is hard to push. Get that fixed, then you can go on to other problems. I agree that a hard pedal would not likely cause the engine loping. However, I also said to check the throttle butterfly to see if it is operating correctly. If there is an obstruction in the throttle plate, it COULD cause the engine to run erratically.