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Hi Guys,
Girlfriend and I went on vacation in her 2005 escape. We get to a moderate grade, and the thing has no guts. Had it floored and was struggling to maintain 35 mph, even if I kept it in a lower gear at close to 4000 rpms. I changed the front three spark plugs in the hotel’s parking lot, but the back three were under the intake manifold. There was no improvement. There was a check engine light on, but I disconnected a terminal when changing the plugs, and it did not come back on by the time I took it into the nearest place (ford dealership). They said their diagnostics said new spark plugs should do the trick. . They said they would be happy to do it for $600(!!!)–I decided to limp it home and try to same some money. The rig has 138k on it, and besides oil changes, she hasn’t had anything done. I changed the air filter (which was filthy), replaced all six spark plugs (which looked awful) with autolite iridiums, and replaced the fuel filter (which was nasty). I also ran some fuel injector cleaner through it.The problem has not been fixed. It’s still running terribly. It fires right up when started cold, and the high idle is fine. When it drops to the low idle, however it starts running really rough. It still has no power and if the engine is warm, it starts rough. Also, when I’m at really low RPMs, it occasionally feels like the power brakes don’t function properly–the brakes work, but the pedal is less smooth and harder to press. To me, when this happens it feels like the soft, consistent, pneumatic resistance from the pedal is no longer there. The check engine light came on, and I got a P0402 code: Exhaust gas recirculation flow excessive detected.
Would a bad EGR component explain this severe of a loss of power? I’m planning on following this guide to check the valve, sensor, and solenoid, but I’m really not sure what my next step will be if this doesn’t do the trick.
http://easyautodiagnostics.com/ford/4.6L-5.4L/how-to-test-the-egr-system-1
Any advice you all could provide would be more than appreciated!
Thanks!
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A plugged up catalytic converter will do this,a back pressure test has to be done using a back pressure gauge.
That’s what I don’t want to hear :). If it was a plugged cat conv, wouldnt I have received a P0420 code, though? Is it possible its something in the EGR? Or is that unlikely to cause such a drastic change? Would you recommend doing the check of the valve, sensor, and solenoid like i outlined before checking the cat?
Thanks!I have seen power losses due to a plugged up catalytic converter with no check engine light on.The EGR system in the Fords,it’s not the EGR valve that is not bad most of the time.It is the DPFE sensor that goes bad or a plugged up passage.
I read that clogged catalytic converter (or three 🙁 ) can cause the problem. It makes sense to me–if the engine can’t “exhale” it’s not going to fly. I’ve read that the DPFE sensor is the culprit most frequently. I guess what I’m wondering (being a complete dummy on this stuff) is could a faulty DPFE cause such a severe loss of power?
THanks again for your inputThis is how you would check for a clogged catalytic converter.
This is how to diagnose a bad catalytic converter.
Here’s more information on solving performance issues.
http://www.ericthecarguy.com/faq/solving-automotive-performance-issues
Good luck and keep us posted.
Thanks guys! Eric–those videos are great, thanks a lot for making those. I’m still confused as to if it was a catalytic converter why it didn’t kick the p0420 code instead. Either way, I’ll certainly check for exhaust restrictions in addition to checking the EGR.
Thanks again!Had something come up, so wasn’t able to get to this as quickly as I would like. Here’s an update.
I removed the vacuum line going directly to the EGR. The idle immediately improved. Then I hooked a vacuum pump up to the EGR. When I put a vacuum on it the rough idle returned. The vacuum pressure did not stay steady, but quickly decreased. I checked the connections between the hose and pump and hose and nipple on EGR and I don’t think that’s where the vaccuum pressure was escaping. I interpreted this as a bad diaphragm in the EGR Valve. Then I hooked the vacuum line back up and headed to auto part store to pick up a new EGR valve. TO my surprise, the car was running remarkably better on the way to the Napa. Unfortunatley, we got hit with a crazy storm while I was in the sotre, and the power went out. I didn’t end up buying the part.So now, the car is running A LOT better. Also, the check engine light hasn’t returned, though it’s probably only been driven 30-50 miles. I’m wondering if somehow I inadvertently cleared a blockage somewhere when testing the EGR valve initially. Does this make sense? I’m still planning on spending the $50 for a new valve and replacing that in the next day or two. While I have the old valve removed, I’ll check where I can for built up carbon.
Does it sound to you guys like this is good to go when I replace the EGR valve? Is my diagnosis of a bad diaphragm inside correct? Thanks a gain for all your helP!
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