I have a 91 ford f150 5.0l truck with a high then low idle. I also misses badly at idle most of the time and when I give it gas going down the road it misses bad. The engine vibrates a lot. I have retrieved the DTC's KOEO= DTC 23 TPS out of range...DTC 12....DTC 34....I have no Idea what to look for other than unhooked sensors or bad sensors I have replaced the TPS IAC cap rotor checked the timing, Looked for air leaks even used propane, Made sure the spark plugs were not fouled. I have no idea what it means when my tps is out of range. KOER= DTC 23 DTC 13 DTC 77 DTC 12....Help would be great...and I have looked for pages to help me diagnose these codes and havent seen any I have found numerous pages of the definitions though but that does not help me find the problem.....I have erased all the codes with my scanner and these are what showed up after the erase.

 

You could read this to understand the out of range code 23, that and 34 being the only one to concern you. I would install new spark plugs & wires if you haven't already.
Ford Fuel Injection » Throttle Position Sensor (TPS)

 

Use this as a reference for your DTC 34 problem: Ford Fuel Injection » EGR Valve Position sensor (EVP)

Both of those code meanings slightly different depending on when they were displayed, KOER or CM. They both mean the sensor feedback is out of range. Use the values listed in both links as a starting point to diagnose and repair the TPS circuit and EGR position feedback aka EVP circuit.

 

Sounds like a wiring or computer problem to me.

 

Email:
Year: 1991
Make: ford
Model: f150
Engine: 5.0l
VIN:
License:
Mileage: 150,000

Key ON, Engine OFF
23 1.(Trucks ONLY): Throttle Position (TP) sensor signal out of range 2.Fuel injector pump lever sensor input is out of self test range (Diesel) 3.(Cars ONLY): Throttle Position (TP) sensor signal out of range
Continuous Memory
63 1.Throttle Position (TP) circuit fault, below minimum voltage 2.Fuel injection pump lever sensor input is less than self test minimum (Diesel)
33 1.(Cars ONLY): EGR valve not opening properly 2.(Trucks ONLY): EGR valve fault / not closing properly / TPS fault (Diesel)


Describe The Problem::
Engine shakes and vibrates at idle every few seconds and Vibrates heavaly upon acceleration
from low rpm.
Previous Repairs:
Ran checks on egr valve and it had low voltage upon opening at 50% But it does not open at
idle so it cannot be causing the vibrate and shake at idle. Checked the voltage at temp ECT
and ohm and it was OK....Checked for vacumm leaks and repaired two of them.....Erased codes
and they came back..BOTH EXUAST MANIFOLD HAVE CRACKS AROUND THEM...Listened to the injector
for clicking sound with stethascope and they were all working...checked for leaks with propane
and found none...I unpluged the iac and it stopped alot of the shake at idle but it still shakes
when driving....Checked tps for voltage and I tested good I just need to adjust it....I also checked the igition timing and it was good.



Key ON, Engine ON
40
12 RPM at idle out of range/high
21 Cooling Temperature sensor out of specified range or ECT out of range
23 1.(Cars ONLY): Throttle Position (TP) sensor signal out of range 2.(Trucks ONLY): Throttle Position (TP) sensor signal out of range 3.Fuel injector pump lever sensor input is out of self test range (Diesel)
33 1.(Cars ONLY): EGR valve not opening properly 2.(Trucks ONLY): EGR valve fault / not closing properly / TPS fault (Diesel)
13 RPM at idle out of range/low
77 Operator error during Dynamic Response Test / Wide Open Throttle not sensed

 

Still sounds like a wiring or computer problem.
If you have the right voltages at the sensors then use a BOB and if you get the same voltages at the computer.

 

The distributor ignition control module was bad. I rebuilt the dizzy and every thing was smooth running.

 

A ICM will not cause those codes.

 

I know right. KOEO test after rebuilding the distributor only reviled a unhooked power steering plug and the tps. I plugged the plug back in and the customer came and got the truck. I did not adjust the tps because I did not have time and he needed the truck.

 

Hi i have a 91 f250 5.0 4sp manual .i cant figure this truck out . high idle on start (3200 rpm with aic connected 2700 disconnected) got code 63 ..ive replaced the tps twice every time when i start her up it idles at 600-700 for 3 minutes maybe then back to 3200 and stays there. ive toke a look at my pcm nothing burned or corroded. ive spayed all over the engine looking for a leak and nothing also during this high idle it doesnt shake are tremble and is not blowing white or black smoke out of the tail pipe. PLEASE HELP
ALSO NEW IAC..EVR SENSOR MAP SENSOR

 

All I can say is it has to be getting air someplace. With the IAC disconnected it should die or close to it.
Is your EGR pipe to the intake broken?
Try disconnecting the green vacuum line to the EGR valve and see if it still does it.

 

LET ME GIVE THAT A SHOT..

 

You should have started your own thread....

If the truck runs at 2700 RPM with the IAC disconnected that means you have unmetered air (vacuum leak) entering the intake system or the throttle is not closing completely (which your Code 63 contradicts). At what point in the KOEO tests and CM display did you get the Code 63 displayed? One is an active problem, the other is from prior history.

 

OK UNPLUGGED THE GREEN LINE ON EGR LINE AND NOTHING HAPPENED

 

Main line under egr valve is solid ive spayed upper manifold and egr vavle and vacuum line with starting fluid also and could find a leak