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2003 Cadillac DeVille
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Discussion Starter #1
Hey,

Friend of mine at work has a 91 Fleetwood with the 4.9 and is having gas mileage problems. I asked him to run codes and he has the following problems:

E48 - EGR System Problem

Where do I start with this one? Valve? Tubes? Evap Canister?

E40 - P/S Pressure Switch

Is this replacable?

E98 - P/N tp D/R ISC Engaged Problem

Is this the ISC itself? Or is there more to this one?

Help needed!! Bahhhhhh
 

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2dfx said:
Hey,

Friend of mine at work has a 91 Fleetwood with the 4.9 and is having gas mileage problems. I asked him to run codes and he has the following problems:

E48 - EGR System Problem

Where do I start with this one? Valve? Tubes? Evap Canister?
Check to see if the EGR valve is operating or not, if it is, check the exhaust passages for carbon deposits causing a clog.
E40 - P/S Pressure Switch

Is this replacable?
This is USUALLY just a bad switch or a bad connection at the switch. It's located on the P/S rack itself.
E98 - P/N tp D/R ISC Engaged Problem

Is this the ISC itself? Or is there more to this one?
It COULD be the ISC itself but it could also be several other items. Check for a vacuum leak or some other thing that could be artificially causing a high idle.
Help needed!! Bahhhhhh
Hope this helps.
 
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