help....check engine light is coming on

[90copcar]

when the engine is under load, at about 3500 rpm the check engine light comes on, then goes off when the rpms come back down. i adjusted the tps switch and it was off a little, but it still does it. if you rev it up in neutral, the light doesn't come on....it also isn't related to speed, just under load...help

 

[90silverstang]

You should pull the codes, I had the same problem, it was the tps-- had a dead spot in it, also my egr sensor was NFG.

 

[rod_351]

egr for sure

 

[Michael Yount]

Pull the codes from the diagnostic port. It's located on the part of the harness that's behind the driver's side strut tower. It could be lots of things - the codes will keep you from playing 'guess' diagnostics.

 

[jrichker]

Dump the codes and see what the computer says is wrong…

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.

See http://www.troublecodes.net/Ford/
OR
See http://www.dalidesign.com/hbook/eectest.html for more descriptive help
OR
See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html

 

[90copcar]

thanks a lot, guys, i will pull the codes tomorrow. i think you are right about the egr valve, or the egr positiuon sensor.....