check engine light comes on and engine loses power

I have a 1994 F150 etra cab 6cyl with 138K miles. when cold the check engine light stays on and the motor won't start untill it goes out or I turn off the ignition and pump the gas pedal
then turn on the ignition. It will start but runs missing and has no power, the transmission won't shift automatically, the exhaust smells like sulphur and gray black smoke comes out. The overdrive switch won't light up and the usual electrical static and engine noise on the radio (AM BAND)goes away and sometimes the radio display won't come on. After a while the light will go out and the engine runs smooth the trans works great and the noise on AM radio comes back, Or I can after a while turn off the switch and usually the light will go out and all runs great. For several hours all will run great, then it will light up again and start missing I have taken it to several shops, but none agree on what the problem is, because they can't read the codes on the computer. When the chk eng light comes on and all the problems occur the diagnostic code reader or analiser they connect to the engine won't work and won't reconize it. How ever once the light goes out the analiser works fine but reports that all codes are cleared and they can't make a diagnostic.Help!!!!!!!!! If anyone knows what the problem can be please post or send email to: ED at snipped-for-privacy@netzero.net or snipped-for-privacy@yahoo.com
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
===========================Sounds like you have a bad ground or power connection. I would start at and near the battery. Because of the corosive nature of lead-acid batteries, connections usually corode near the battery. Check and clean the battery cables and look around the battery for corrosion on powers and grounds. GL
--
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com ).
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Scott opined in ...

After checking that, check the engine to firewall/body grounds then the harness to body ground next to the PCM (computer).
BUt it sounds to me like you may have a problem in the module itself.
If the above doesnt do it, find a replacement in a scrapyard, same model/engine/trans of course.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.