please help engine cranks no start

[slow_SHO_93]

for the last couple of weaks when i turn the key to the run position my 93 atx
goes into self diagnostic mode it also dose this right after i start the car.the car idles high the fan comes on. and the cel comes on when put into gear drive or reverse the idle comes down to normal usual the engine runs rough in the lower rpm range but runs fine abought 3500 rpm mpg really suck im only get 11 mpg.today while sitting in the drive through at mcy ds the car died would not restart.i replaced the dis moduol no help. the car set for 3hrs it started and ran for 30 sec then died no restart. checked and cleaned all grounds.cps,cam sensore coil,plugs ,wires all done 2yrs ago.ialso tried a ccrm off a running car. i had d4u1 comp out of a 94 i switched back to the stock 93 comp. ican still pull codes the only code is a 172 lean code. please help this is my family car.(its hard to fit the wife and three kids in the back of a 93 cobra leaglly.)

 

[ilikepoultry]

sounds like a crank sensor - i've only had this twice in the last month

check to make sure there's no paper clip or similar in the connectors (where you check for codes)

11 mpg??? o2 sensor?
172 points to the o2 sensor

 

[ohfosho]

sorry its hard to read what you wrote. but from what i get: with the D4U1 compu plugged in, it stays in code testing mode (even though im sure you must have checked and made sure you didnt leave a paperclip or code reader hooked up), but when the original 93 compu is hooked up it is not in diagnostics mode?

this would say that the D4U1 compu is bad.

 

[sdpatt]

The EEC is still in the diagnostics mode and you are running the KPER test when you start the car. Check that test plug for a jumper or a short.

 

[slow_SHO_93]

the car goes into diagnostic mode with ether computer in the car there is no jumper or paper clip i use an obd1 scaner from work .i run a fast **** shop. all this started shortly after the ford dealer installed a new transmission in late febuary.after letting the car sit for a day it started right up . i didnt run it long enough to see if it died.
any idea whitch wire in the plug could be shorted? thank for your ideas so far