96 3.0 dohc egr problems

Hey guys i got a 96 lx with 144,000 on a 3.0 dohc. It runs pretty good but i have an engine code for p0401 egr flow insufficient. I replaced the egr valve cleaned the passages and replaced the dpfe from autozone (50 dollars). I had the code cleared at autozone and today i was taking a 50 mile trip on the highway and the code came back again. I am wondering what is left to replace or if i possibly got defective parts. Any help would be great.

did u check for any vacuum leaks with the two hoses connected to the sensor?

no leaks that i can hear. I had one before and i could hear it but i replaced the pcv elbow and that solved it. I checked for leaks with a scope and found nothing, also the engine is not running rough like it would with a leak. any other ideas?

did u check the down tube from the exhaust pipe to the base of the egr? and make sure to check for cracks in sensors especially at the seams in the plastic and the entire vacuum line.

I did not inspect it closely but i figured that since it wasn't emitting a loud exhaust sound that it wasnt leaking. Just about all the sensors are new so i dont know where to go next.

possibe defective part maybe, i can't think of anything else

I cleaned out all the ports again and put everything back together with new gaskets. I had autozone clear the code and i drove it for 30 miles without a new engine light. Is it safe to say that it is fixed? thanks, jon

i think you'll be okay. any leaks in the gaskets, and the egr will cause a low flow as well as an obstructed tube especially with a dpfe. g'luck with it. if i recall you said you replaced everything to do with the egr system, right? then i can't think of any other reason for the code.

yeah i did. another day without the light so i hope its solved thanks for all the help

darn light came on while i was on my way back from work. same code again. could it be that autozones egr pressure sensor is crap? i've been told only to use ford parts on sensors. anybody else had this problem? this is getting really frustrating

do an ohms test on the sensor and do a through vacuum check of the hose to egr valve with a vacuum pump gun.

also i forgot autozone used to have a small booklet black and white on how to test all the sensors for engine management.

i will take the old one in today and get it tested to see if it was even bad
thanks

take the old and the new one to have them both tested.

also don't forget to check the egr solenoid it will next the egr backpressure sensor look at the vacuum hose routing on the veci sticker the vac source is the intake manifold to the solenoid to the egr. check for leaks. also see if autozone will lend you a vacuum gun to test the egr diaphram and the vacuum source, look for a steady needle on the gauge.

also make sure the air pump is working correctly.

the sensors checked out ok so i took back the autozone one and put the ford one on. of course the engine light came back on. vacuum hoses are good i checked for leaks again. this is getting irratating