Performance issue

[MeddieFrac]

Im gonna drive this car off a cliff

95 Ford Ranger 4 Cyl Manual Trans, there is a vibrating noise around eminating from the throttle body area; the car idles very high (when you pull up at a stop light and put it in neutral, the engine stays revved up like it's still in gear.

When you shut the engine off, it turns over several more times, putters to a stop and shakes the body of the truck.

The more I drive it like this (b/c I can't find a mechanic willing to spend the time to diagnose an old vehicle w/ a low profit-margin on repairs) the more I am hearing disconcerting noises while on the road.

DISCLAIMER: I MAY HAVE CAUSED THESE ISSUES

I bought the truck 2 weeks ago, and it had low idle/stalling issues.

I cleaned the MAF sensor and put in a new air filter, with 20% better idle. Then I cleaned the throttle body, but the butterfly plate was so caked with dirt/grime, I've never seen such build up of grease in my life, so I took off the entire throttle body in order to free up the butterfly plate.

I replaced the throttle body gasket, b/c the origonal was torn.

After this, the engine now idles TOO high, and shakes the car when you turn off the engine (engine putters to a stop/turns over several times before turning off completely)

I sprayed carberator cleaner and couldn't find any vacuum leaks.

Please help before I push this truck off a cliff and fling myself off the cliff with it (and I'm not joking)

PS. I checked one of the spark plugs and it looks like its 10 years old, its even starting to rust

 

[adsm08]

Have you reset the memory yet? That stuff didn't build up over night, and the computer had time to learn the changes gradually. Then you came along and took it off all at once but didn't tell the computer.

 

[MeddieFrac]

how do i reset it?

 

[Mark_88]

Disconnect the battery ground for about 20 minutes should reset it...IIRC...but I think I'd read somewhere something about disconnecting both battery terminals to do it properly...I'm sure someone with more knowledge will elaborate on that point...

The high idle does sound like a vacuum leak...and maybe something like a hose disconnected...

EDIT: Maybe the brake booster...or the TB is not sitting flat on the intake.

The high RPM may be due to too large of a gap so you might not notice any difference in the RPMs by spraying the cleaner around the TB...sounds like it is drawing in major air somewhere...

 

[martin]

As the idle issue went from one extreme to another after you removed the tb and cleaned it, logic suggests that the problem should be related to the area you worked on. You said you went around with cleaner to check for external leaks and found none so this suggests the problem is internal to the throttle body, mechanical or electrical. The three things that come to mind are, butterfly not closing completely, iac stuck open or tps incorrectly adjusted.

 

[MeddieFrac]

excellent martin! when I took off the throttle body, light can be seen around the edges of the butterfly plate when its in the closed position and i put it up to the sun. shouldnt it be air tight around the edges? perhaps the butterfly plate is out of alignment?

 

[Insanejughead]

Most likely the gunk has gotten into the shaft of the throttle body. Clean and oil all of the moving parts. Also, check the spring tension on the butterfly valve shaft. I doubt it has lost much of it's tension, but time and heat can do things like that to springs.

Also, make sure your cruise control isn't keeping the throttle body open when it's hooked up.

 

[zekew64]

Most likely the gunk has gotten into the shaft of the throttle body. Clean and oil all of the moving parts. Also, check the spring tension on the butterfly valve shaft. I doubt it has lost much of it's tension, but time and heat can do things like that to springs.

Also, make sure your cruise control isn't keeping the throttle body open when it's hooked up.

+1 on the cruise control...when I put another motor in my truck, I hooked up the cruise, thinking it would work, come to find out that the inhibitor solenoid is bad. What happened with mine is that it would idle high and go higher; I disconnected it, and haven't had problems with it since. Also, check your EGR system; your vacuum leak could also be the vacuum solenoid, the EGR valve itself (which could be carbon-caked as well), or your vacuum lines themselves could be cracked.