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1991 Cadillac Fleetwood(FWD)
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3 Posts
Discussion Starter #1 (Edited)
Hello guys. I wondering what the problem could be. :hmm: When it's cool weather it's fine but when it's get hot outside and it's been rolling for a while, you can hear and feel the engine start choking losing power going in and out untils it ultimately stalls. The car start bucking and jerking till it loses all acceleration power. After the car cools down, it's back to normal again. Is it the fuel pump relay or the fuel pump itself? Or is it the Throttle Position Sensor? Computer codes is E48.
 

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2010 DTS
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87,430 Posts
Probably the fuel pump is going bad. Outside temperature is only coincidental and most likely has nothing to do with it. Put a fuel pressure gauge on it with a long hose and tape the gauge to the windshield. I'll bet you see fuel pressure falling when this happens.
 

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1991 Cadillac Fleetwood(FWD)
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3 Posts
Discussion Starter #3
Probably the fuel pump is going bad. Outside temperature is only coincidental and most likely has nothing to do with it. Put a fuel pressure gauge on it with a long hose and tape the gauge to the windshield. I'll bet you see fuel pressure falling when this happens.
Yeah I would but it happens so so rarely that it'll be hard to catch it. I only have problems like this during the hot summer. I just pulled the air cleaner over the throttle body. I looked down there and there is a little crud in the egr tubes. Otherwise the throttle body is clean as a whistle. I pushed up on the spring in the Egr valve and they went up but with a little force. I wonder how easy should the spring push up?
 

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85 Coupe Deville 4.1 V8 & 4.3 V6 Deisel & 1970 Eldorado
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773 Posts
Also check to see if you have a clogged fuel filter. Do not discount the possibility of a failing ignition module. These are noted to fail with heat.
 

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2010 DTS
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I pushed up on the spring in the Egr valve and they went up but with a little force. I wonder how easy should the spring push up?
As best as I can recall it should not take a lot of force to lift the EGR diaphragm on that type of EGR valve.
 

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2011 Crown Vic LX, 2009 Chevy Malibu 2LT
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Since you have a known problem that can cause poor idle and low power, start there before moving on to diagnose other things like fuel pressure. Fix the EGR and then continue.
 
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