I have a 1993 F150 Flareside with a 5.0L , 5 speed and 4wd. Over the weekend, I had a coolant leak, the tube on the bottom of the throttle body cracked. I took the throttle body off to see how to fix it. I read on the list today that you can just by pass the hoses and not run the coolant through the throttle body at all. Seems like an easy enough solution.

Anyway, while I was at it I changed all my hoses and thermostat. I cleaned the throttle body with throttle body cleaner and then reinstalled it with a new gasket. I plugged all the connectors back together. When I started it, it had a high idle, ~2000 rpm which slowly dropped to 1500 and stayed there. as it warmed it began to run rough. I double checked for vaccum leaks and all the connections, no leaks and all connectors looked okay. While it was running, I unplugged the TPS, it went up to a high idle, but seemed smooth. When I plugged the TPS back in, engine still running, it got real rough, slowed down to nothing and chugged a few times and stalled. It runs like crap when I try to restart it. I disconnected the battery to see if the memory would erase, but no good.

Now what do I do? This is my daily driver. I need help and advice on what to check and how to check it. Please help me out.

BTW- it ran fine right up until the coolant leak.

Regards,
Ed

 

Sounds like the tps. Thsi will cause all kinds of idle problems. Did you get any cleaner in it?

 

Not intentionally, but I soaked it pretty good to get the 150,000 mile worth of crud off of it. Some cleaner and gunk may have gotten in to it. I has to be something like that, because it ran fine before. The only things I can think of are the TPS or air valve. I will check the TPS tomorrow. Any good methods on how to check it?

Thanks, Ed

 

Okay, I checked the codes and TPS this morning. I get code 22 (BP sensor or MAP out of range) and code 122 (TP sensor circuit below minimum voltage) I cheked the TPS with a volt meter in the KOEO mode, the votage for the 3 leads to the Signal Return Pin are .080, .076 and .075 the service manual says .34 should be the minimum and 4.84 is the max. When I move the throttle to wide open, the voltage remains the same, 080, .076 and .075.
Is it safe to say that the TPS is no good?