my truck is a 1999 with the 5.4 and is showing a P1451 which states.


P1451 Evap. Emission Control Sys. Vent Control Valve Circuit Malf.


does this mean the purge valve on the firewall above the brake booster needs to be replaced or what. when I had my new engine installed they told me that code and then told me that its the valve on the firewall above the brake booster. is this true.

 

No. That is not where the Evap Vent Solenoid is located. That is located under the truck, right near the spare tire. Almost always this is a wire that's rubbed through, but it could be a bad solenoid. Climb under there and locate it and inspect the wiring. It is number 9 in this photo.

 

great thanks a million so the one on the firewall is the purge valve correct. will this cause poor MPG or not just wondering. also question that's not for this subject but a bad muffler will cause bad MPG correct.

 

I live in IL and it's time to have my emissions tested so since I have a SCT programmer with a custom tune from MPT, I took the tune off and set it back to stock.. I have NO cel but when I check for codes with the programmer it tells me I have a p1000 code which says the obd 2 monitor testing not complete which I believe just means that the computer hasn't fully reset.. does anyone know how long it take for the computer to reset?? How many miles you need to go?

 

I have a few code on my truck and was wondering if y'all could help me out. The codes are p0455
P0136
P0156
P0401
P0301
P0304
P0171
P0174

I reset the light with my code reader and I drove the truck around and then It piped up again with the too lean codes. On the way to school it started to rough idea missfireing and loss of power. The check engine light was blinking and I've never seen that before. So I'll post the new codes(if any) when I get home but in the mean time what can I do to fix the miss fire and the too lean codes. Thanks fbf150

 

What are you driving? First you need to fix 301 and 304. Once accomplished, reset and go from there.

 

im sorry totally forgot that. its a 1997 ford f150 with a 5.4l Triton. also update i have gotten the codes down to a few codes miss fire in no.1, egr insufficient flow, and too lean on bank 1 and 2

 

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i have read that the DPFE could be the cause for the misfire and the lean codes. do you agree? but here is the funny thing about this misfire its not a constant misfire it only does it every now and then like itll drive fine then itll get rough and the idle is horrible and then itll fire every now and then on acceleration. i dont know what this could because everyone is saying its ether a solid misfire or no misfire. also thanks for the help.

 

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