On my 93 Bronco with a 5.0 5 speed i am having idle problems!!!! First of all i have replaced just about everything that can be replaced on this truck, except the tp sensor. My problem is that when i go to work i take the freeway, truck is fine. Up until i get off of the freeway and come to the first stop sign. Then while stopped the idle hangs around 1500rpm and when i take off and shift the idle raises to 2500-3000rpms on its own. At first i thought it was a vacuum leak but i replaced all the vacuum lines, sprayed the engine with ether(found no leaks), replaced the egr due to a misleading smoke test, replaced iac, checked codes and got different ones every time i checked. I'm stumped on this one. Could the tp sensor be hanging up and causing high idle? And i have checked the forums and found some info on the idle screw adjustment procedure but i haven't found the proper way to actually do it. If anyone can help me i'd greatly appreciate it.

 

Two questions. What codes did you get? And, owning a bko, are you registered to this site?

FullSizeBronco.com

 

the tps and the IAC is the first to things you should chek if bad idle..

replace your TPS thats your prob im 98% shure

 

Don't just replace the TPS. There are ways to test. Look at this.
Ford Fuel Injection Throttle Position Sensor (TPS)
Do not adjust the "idle screw". It is not a idle screw, but just a throttle plate stop.
It sounds as if you may develop a vacuum leak after the engine is hot. Did you check for leaks when cold or hot?

 

I checked this thing cold and hot. I've checked after a long freeway run. I've tried almost everything that i can think of and pretty much everything others have suggested. I do belong to fsb.com and i didn't get any closer to a solution posting on their site. As for the codes i got they were as follows:31,32,52, and 77. These codes were at different times of checking, not all at the same time. I thought it could possibly be related to the cruise control, because it only happens mainly in the morning when i can use cruise, but in the pm there is too much traffic so i don't use the cruise and it seems to not happen. This weekend i'm going to check the tps voltage and maybe replace the sensor since it has at least 100,000 miles on it.

 

I can't remember, but is the cruise on our trucks vacuum operated?

 

1993 was the first year for the non-vacuum new style electronic cruise system on the F-Series/Bronco.

dn.

 

Wilevel2,

My truck does this occasionally. Every time it does, I shut off the truck, get out, and spray the springs and pivots on the outside of the throttle body and the problem goes away for about 8 months to a year.

Before you spend money on parts, know that DIRT might be causing the throttle to occasionally stick.

 

mine is doing this... I need to check my TPS. I am getting a code about the same time while driving? Will a KOEO test pickup that code that keep getting thrown?

-Randy