Ive got three signs something is wrong, but dont know what the verdict is. I first noticed my gas milage average dropped to about 11mpg. (normally 16mpg) The second thing i noticed was a sort of burning smell coming from the exhaust. (definitely not anifreeze, i know that smell for sure) Lastly, i touched the inside of the tail pipe and there was a ton of exhaust soot in there. I looked around in the garage and saw more soot on some toys that were next to the exhaust pipe. (i keep the truck in the garage overnight.) there is no oil leaking from the truck, but it does seem to burn a little oil. (about a quart low after 3000 miles) The truck seems to be running fine, for now.

 

cat is bad.

 

thanks for the suggestion. I was wondering if the smell might be the catalitic converter...
i was thinking the spark plugs might need to be changed and a little tune-up might be in order. Could the tune-up possibly fix the problem, so i would not have to get a new Cat? i think those run pretty expensive, right?

 

its the cat. just remove it and replace it with a straight pipe. thats cheap. unless you have inspection

 

The only other thing it could be is bad upstream O2 sensors. If they are making the engine run too rich, the cat wont work efficiently. Are you throwing any codes?

 

what's the "bad smell" actually smell like? (curious)

on initial start, my truck reeks of what I believe is exhaust...
I haven't noticed if this has dissipated since the front crank seal was replace (it was leaking)
I've also got a ton of soot at the exhaust tips, which I usually just wipe away when I see it every week.

I had a cat go on my old car (`02 Nissan Sentra) a couple years back, but never noticed any terrible smell, or bad soot.

 

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check engine light popped on today... i'll have it read today after work and let yall know tomorrow. The more i research, the more i hope it is just the Cat, as i have found one on the net for $98. We have to pass state inspections in TX, so no to the straight exhaust. The smell is not immediate when the engine is started, only when it gets warm. But it is very strong. I have researched replacing the fuel filter, and it looks like the whole pump would need to come off as well, maybe even replaced too. (fuel filter is inside the pump, as i understand it) Hopefully i will have some good news to report tomorrow...

 

yeah I was gonna say my magnaflow cat plus fully welded install was only like 150-200 if I remember right. and it would have been a lot less if I would have got it done when I got the exhaust on. im not a hippy or tree hugger by no means but its not a race car just replace it with a aftermarket cat...pref magnaflow and be done with it. O2 sensors may be something to check first tho. And yes from when I checked into the fuel filter I figured out that its in the tank to.

 

So i've got 2 codes. One kinda makes since, the other one is off topic.
P0171 - possible solutions are: oxygen sensor bad, ignition misfire, or fuel injector problem

P0551 - possible solutions are: power steering pressure switch bad or loose.

i will get new plugs, a good tank of gas (higher octane), use some injector cleaner, and go find a Cat.

I havnt got time to worry about P0551 right now, but any ideas on that?