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I hope I’m in the right spot if not please tell me. I have a 1993 F250 5.8 58k original miles lately it’s developed a skip or miss in the engine. The truck will idle high no tach. Probably 1500 or little more or less. If you shut the truck off and restart it it usually idles at what seems to be the right idle speed. Sometimes it will fluctuate high then normal idle back and forth. When it idles high the check engine light comes on. At highway speeds it may surge I guess. You can feel it slightly. Feels like slight loss of some power. Not a lot but I can feel it. Sometimes it feels almost like it loses spark for just a second. Like the engine dies then starts right back up. When I’m on the gas feels like a vibration I’m guessing from a miss. When I let off the gas the vibration goes away. I put new pcv valve, pcv filter, air filter cap and rotor in last day. it Has not skipped and seems to run smoother since I did that stuff. I did a check jumped with a wire for codes. truck off key on. Best I can tell since first time I ever did it. Code 122 tps low input? 123 tp circuit high input? 128 map sensor? im not really sure what to try next. It’s slow time at work usually laid off by now. But down to 8hrs so I’d like to see if I can fix it before it goes to a shop. Anyone that would take the time to give me some advice I would really appreciate it.
I would take your diagnostic check a step further and run the Key On Engine Running KOER portion of the test. Get engine to running temp and then test. Key On Engine Off KOEO test issues should be done before you work on these codes but you will have a better idea of what might be going on. Current Memory code 212 is usually the PIP located in the distributor. Here is a good thread on what might be your issue and there are two ways to repair it if it is the problem. Plenty of threads on this issue. Sandy https://www.ford-trucks.com/forums/1...in-memory.html
I did some work today changed the tps I already had it. Found a lot of vacuum lines cracked or just looked bad. So I changed them all even if they didn’t look bad. Cleaned the tb. Ran without a miss for the 4 miles I drove it. Still idles high. Now the only code is 22 that seems to be map sensor from what I read. Going to look probably just change it. It is a old truck I don’t see it as a waste of money. That may help the high idle not sure. Then see how it runs and if more codes come up. I was thinking about the pip other guys at work mentioned that. Thanks for the replies. I’ll let you guys know how it works out. Still a little worried about the 212 maybe a fluke code see if it comes back. It’s low miles and still has a good body so it’s worth spending some money. And it’s probably my second favorite body besides the 78-79 body.
Now the only code is 22 that seems to be map sensor from what I read.
Your truck should display three digit codes, not two AND three digit. Code 126 and 128 does indicate a problem with the TPS. Could very likely cause your high idle.
Originally Posted by Rb622
Still a little worried about the 212 maybe a fluke code see if it comes back.
If you counted flashes then this code very well could be a mis-interpretation on your part. The correct definition is: Loss of IDM input to EEC or SPOUT circuit grounded. It has nothing to do with a black versus gray colored Ignition Control Module (ICM) since your truck uses the older Push-Start ignition system. The IDM signal is generated via a 22k ohm resistor on the coil primary circuit. As you can see from the code definition there is another possibility " SPOUT circuit grounded".
I’ll have to pull it off and look at it. I had that in the back of my mind. I changed the tps that don’t mean the one I put in is not faulty. I’ve heard of that before. The vacuum hoses were definitely bad. They were beyond shot.
I replaced the map sensor since I already had it. Engine not missing at all anymore. Not stalling skipping. Still isles high. It fluctuates most of the time up down. When I first start it it runs fine. Still have code 122 I think I miss read it last time when I said 22. I’m going to check the pmc and icm resistor. Now I’ve thought of something else. After watching a YouTube video. My one plate on the tb I can see a slight gap. Light through it when it’s closed. Could this allow air in causing the high and fluctuating idle? From what the video said it was on that car. Would that throw a 122 code? I know it’s tps. Also is the thing I’m pointing to in the picture need a hose going somewhere? I don’t have any idea what it is but it’s blowing air.
Now I’ve thought of something else. After watching a YouTube video. My one plate on the tb I can see a slight gap. Light through it when it’s closed. Could this allow air in causing the high and fluctuating idle?
There is supposed to be a slight gap between the throttle blades and body. It's there to prevent the blades from closing too far then sticking in the throttlebody bore. If only one is showing a gap then you may have a worn throttlebody or a bent TB blade shaft. If the TB blades are too far open, yes that will cause a high idle. Fluctuating idle...it could be a contributor if the TB is worn. Same for a TPS.
Originally Posted by Rb622
From what the video said it was on that car. Would that throw a 122 code? I know it’s tps.
If the throttlebody blades are set too far open then I would think you would get Code 121 (KOEO) Closed throttle TPS voltage higher or lower than expected.
I tested the Tps sensor.
the ohms read 1.91 I’m told you want it close to 2 so this is within range.
volts read 4.99 so that’s in range
the signal is off I did this test over and over got the same every time
1.82 then when I turned the throttle would fluctuate 1.82-1.85 so it’s not moving near enough.
I’m assuming with these tests the tps is not working right needs to be taken back.
it should also be telling me the computer is communicating with the tps correctly.
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