i am trying to help a friend of mine who has a 2000 extended cab f-150 4x4, 4.6 auto with 80,000 on it. it was skipping and idleing rough so he had autozone scan it. that came back with an egr valve. he bought one replaced it and the truck ran worse. took it to a mechanic and he said the egr valve was indeed good, possibly a dpfe valve? i didnt even know what that was.anyways the mechanic did some stuff to the truck and it is no better. he didnt get charged, but it still skips. then the tech told him to drive the truck 100 miles to reset the computer then he could pull codes. so, is there any other way to reset the computor without driving a poorly running truck 100 miles, and what else could this be. Im sure someone else has had similar problems. thanks in advance.

 

Try disconnecting the battery for 30 minutes. Not the best way but will work. Most auto repair shops can reset the codes. I would imagine your
friend has either a bad cop or bad coil pack. Not sure which is on his truck.

 

Disconnecting the battery will reset the computer, but the comp needs to collect data, hence the "drive 100 miles".

Not sure what is magical about 100 miles, but my sister in law just went through this last week having her car inspected. The day prior she had her alternator replaced and then her car inspected. The inspector connected to the car and checked for any codes, several sectors said "Not Ready" and he asked if the batt was disconnected. She said yes, and then was told to drive 100 miles and come back.

 

there must be another way. it seems possibly harmful to drive a skipping motor 100 miles to get the sensors to read correctly

 

Have you checked the vacuum hoses going to the dpfe sensor? That would be a good starting point if its missing and has dpfe or egr related codes.

 

i have not. also not to sound dumb, but what is a dpfe and what does it do?

 

The problem in trying to solve your problems is lack of background information by AutoZone, the mechanic and the owner.
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First you need to know what the code/s are. The codes do not tell you what parts to replace, only the system in fault.
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Secondly, the mechanic should have known how to address the issue with a scanner that told him what system is in fault and service from that info.
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Thirdly, when a PCM is either cleared OR powered down to reset, the PCM has to begin all over again to test each section with diagnostics.
The first result the emmissions test station saw was a code 1000 as a basis of rejection. Note that the code 1000 does not set a CEL on so you don't know it's there unless a scanner, that can see it, shows it.
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There are at least 7 Pid sections that must be tested to PCM satisfaction before all are reset to a passing condition.
When completed, the code 1000 clears.
The section that takes a large amount of test time is the fuel tank evap testing..
Some tests require multiple drive cycles.
The actual fault code/s need to be seen and recorded, then address the system for a fault with any hardware involved and not guess at what part is causing the system fault.
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This is why the owner is haviing a problem getting the issues solved.
It's much more complex that thinking things are so simple.
It's a computer controlled system and must be addressed in that light.
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Get the fault codes first. If it is the EGR system, the codes will be in the 04xx number series.
Provide this info for us to give some help.
Good luck.

 

thanks, i will get more info from him and post it up to get your help

 

Differential Pressure Feedback Exhaust gas recirculation it basically sends a voltage to the pcm to tell it if the egr valve is functioning.

 

Not sure if this is even relevant,but had the same issue on my 97 XL 4.2.
Replaced the EGR valve,and code came back.Purchased a DPFE sensor,and cleaned out the EGR housing ports,as well as the main exhaust inlet to that housing,and the return port into the intake. No more CEL.....My original DPFE sensor was made of a metallic material,that had corroded due to the inherant moisture in the exhaust stream.The new one was plastic.Traded in the ole girl shortly after for my present 07 with the 4.2,automatic.
Miss the ole 97,as she never let me down,but Love the 07....