vibration help!

[bustetter]

I own a 2002 ranger with the 4.0 engine 2wd supercab. The idle isn't that good and when i put it in drive and accellerate, it vibrates untill I hit about 15 mph.also if I put my foot on the brake and give it some gas it vibrates. If I put the parking brake on and give it some gas it doesn't. Can someone please help me.

[pshirkey]

check the engine/gearbox mounts/driveshaft universals,somethings not secured properly or seriously out of balance.

[bustetter]

It's not my drive shaft or tranny mounts i know for a fact because i already checked those. I still need to check the motor mounts really good though. when i hold the brake down and give it some gas it just sits there and vibrates. it doesn't do that with the parking brake on. My differential is also leaking from the front seal where the drive shaft yoak goes.

[bustetter]

I also forgot to tell you all that on some occations it is hard to start and it mostly does that on a slope.

[bustetter]

do you think that the occational hard starts(which also happen on flat ground, too), poor quality idle, and vibration apoun acceleration could be attributed to a bad coil pack or ckp and cmp sensors or something else. I also have noticed that the fuel economy is bad. By my rough calculation I am only getting about 14mph. From what I can see my motor and transmission mounts are fine and my U-joints are fine. I haven't found anything wrong mechcanically. I jacked the rear end off the ground (just to see what would happen)to see if I could recreate the vibration and I couldn't. I also noticed that on cold days when I start it up, it goes strait to 1000rpm ,it trys to go adove it, but it just can't. If I blip the throttle it will go to about 1500rpm like it normally does. any ideas?

[BroncoJoe19]

Sorry I missed this the first time you posted.
You probably have a vacuum leak, and it may be located in your brake power booster, that would explain why it is worse with the brakes on, but not with the hand-brake on.

Tips for Checking for vacuum leaks.
Some of the sensors and some of the actuators either read the amount of vacuum, or use vacuum to move controls, therefore it is important to the proper functioning of the engine that your vacuum system is fully intact. Otherwise one may get codes falsely indicating that there is a problem with a controller/actuator, or a sensor when in reality it is caused by a lack of vacuum.

Look at your rubber vacuum hoses (they are about 1/4 - 3/8 inches in diameter, if they are dry rotted or cracked, replace them. IF they slip on/off of their connectors too easily, they may have stretched out a little bit, cut the ends off, and put them back on.

You may listen for a leak. Sometimes using a cut off piece of garden hose is a good aid to listen with. Sometimes a cardboard tube (like from gift wrapping paper) is helpful. Just remember that whenever you stick your head inside a running engine compartment, that you are not wearing any loose clothing or jewelry that can get caught.

Another suggestion is to use a spray can of carb cleaner and spray around the bottom of the intake manifold, and the base of the throttle body assembly. IF there is a leak, you should hear a change in your engine.
Keep a fire extinguisher handy, or use water instead of carb cleaner (it works, but not as well.) Be aware that if you use water and the wires get wet and it runs worse... your wires may be bad, and the water is allowing them to arc instead of jump the gap of the spark plug.

Another suggestion is: to take a propane torch, turn it on (but don't light it) and move it over the vacuum hoses and connections. The engine RPM's will increase if there is a leak and the propane gets sucked in.

Courtesy of TheOldWizard ford-forums... Don't forget to remind folks to check the PCV valve, hose and grommet !

Courtesy Ramnasal ford-forums... Clamp off the hose that runs to the vacuum booster (brake booster) or pull it and plug it. It is possible that the diaphram on the inside of the booster may go bad and cause a vacuum leak.

And one more place that is not always obvious is that the vacuum reserve canister in older vehicles sometimes rots out and leaks, but rarely gets checked. In older vehicles it looks like a metal juice can, in newer vehicles it is made of plastic.

Here are some pictures of some vacuum lines in a 1998 3.8L windstar.
Ford Forums - BroncoJoe19's Album: 3.8L vacuum lines