tyler165

Hi there, after scrolling through countless threads on issues close to mine I figured I’d make my own. So a little context…My truck is an 07 lariat. It has 195000 km on it. I just bought it recently and it was bucking at 2000 rpm when stepping in it on the highway. Previous owner drove it like this for an unknown amount of time but I’m assuming awhile because they were afraid of the evil plugs. Well, so am I. So I sent it in to cam Clark Ford in n Vancouver to have them do the plugs, and as it would turn out the coils as well. Truck still running crappy now getting a misfire code on cylinder 5. Swapped plug, code gone, new code. Secondary ignition, cylinder 5 so I changed harness plug that plugs into coil and that problem gone. Now though I’m getting a po171 bank 1 lean code and it absolutely gutless. Will rev up at an idle but will barely make it to 2000 rpm when driving. I can’t find any vacuum leaks, I’ve changed the Maf sensor, my bank 1 sensor 1 is cycling up and down like it should on the reader. I did notice though, that the bank 1 sensor 2 is mimicking the 1st sensor. So is the bank2 sensor 2 for that matter although not as much.. I’m assuming my cats are plugged.. would this leave it gutless? And would it make it throw the po171 code or even better are the cats plugged as well as having a vacuum leak somewhere.. any info would be appreciated. I’m basically looking at cats next but these are pricey and don’t want to buy them for nothing.
Thanks in advance for any advice.
can’t seem to upload video, the other one showed 2 sensor shooting up and down between top and bottom like the first..

Jimboy

P0171 Causes

• Intake air leaks
• Faulty front heated oxygen sensor
• Ignition misfiring
• Faulty fuel injectors
• Exhaust gas leaks
• Incorrect fuel pressure
• Lack of fuel
• Faulty Positive Crankcase Ventilation (PCV)
• Faulty Mass Air Flow (MAF) sensor
• Incorrect PCV hose connection

If you are seeing the same wave form on the upstream and downstream O2 sensors your cats are probably bad and in your case the poor performance is likely due to clogged converters, my opinion.
My experience with a cat purchase
Catalytic Converter-Direct Fit Left Eastern Mfg fits 06-08 Ford F-150 4.6L-V8 was ordered from e-bay $162
Perfect fit and cleared my P0430. Inspection of old converted showed it to be empty. Its been two years and no new codes.

tyler165

Thanks for the reply, I have replaced my Maf sensor,(probably should have tested it first) made no difference. Changed fuel filter, have good psi at the rail and dealership that did plugs said pressure was good(although they’re probably only going off readings not actually plugging into the rail.) Have sprayed all vacuum connections I can see, (is it actually possible to get your hand behind it to the one that’s suppose to be in the back?) As for the cats, thanks for the link I’ll check that out.

Jimboy

Are you a 5.4L?

tyler165

Yes.
sorry probably should have mentioned that.. 🤦‍♂️

Jimboy

tyler165,

Any update?

jimboy

tyler165

Cats are being delivered today!

tyler165

So replaced the cats, power is back and idling issues gone. I think that was my problem.

Jimboy

Those old cats are worth $200-$300 each. Take them to a recycler that specializes in cats. Scrap yard will give you $20 for both.

laterongc

If you are up for sharing, I’m curious to hear which cats you bought and a approx summary of costs (cats, install, and if applicable sale of old). Thanks.