New O2's, now P0155, P1151, P0161
 

1998 4.6L Expedition 152,000. I just put in new upstream O2's to improve mileage, but just after I put them in, she starts spitting out codes P0155, P1151, P0161 and she's idling rough.

I've just done a lot of work up top because of a dirty fuel injection problem. All I've done so far:
new fuel filter
new PCV valve
new vacuum hoses
cleaned MAF
plugs/wires
obviously O2's
new starter (probably not related)

I'm looking into the EGR valve today to see if it's got a problem.

Thanks,
Soder

probly not a EGR valve but a good thing to check and you need a vaccum pump to do it i used a hand vaccum pump from a brake bleeder kit start it up then apply vaccum and should really run rough and if stays the same the egr valve is bad

they hardly ever go bad look up rough idle on the search is a common prob cause by alot of reasons

if you have done plugs and wires try cleaning the throttle body elbow body ports for the egr valve they commonly plug up with carbon and cause rough idle it was the cause of it for my 4.6 you will need pipe brushes carb cleaner or something just as good and elbow grease


hope that helps

Go back over your O2 install. Check the terminals for corrosion. Wires for chaffing. Did you buy universal sensor where you have to pin the connector yourself or the kind that just plug in. Any wires chaffed? The fuel injectors, O2 Sensors and the MAF share the same 12v power source. While all these codes are for the rear sensors a tug on the harness when connecting the front sensors could trigger this. Did you do anything to the injector connectors or the MAF?

JMC

Hey Redneck Marine,

Where did you get your add a leafs?

I haven't messed with the injectors or MAF since they've been cleaned. I bought OEM replacements that just plug in. I wen't back and checked the connections and cleared the codes, but we'll see if they show up again. I haven't had a chance to drive it much since I checked the connections. I did tug on the plugs a bit to get the old O2's off. I hope that didn't mess up anything.

Well, for anybody else that has this same problem...here's the solution. The codes popped up again so I broke down and paid the $65 for a diagnostic. Turns out the "OEM" O2's I put in were not exactly OEM. They were Bosch from Checker/Kragen. The shop recommended either the OEM Motorcrafts or the Denso's they put in. My plugs and wires were also cheapo's and two of my plugs were cracked.

So, high quality O2's and high quality plugs and wires fixed the problem. Now she's running great.

Just one more piece of evidence that with these engines, you really should go with Motorcraft or high quality.

Thanks for the suggestions and quick posts everyone!

summit racing but you can find them anyware about 80 for the pair there super lift but rancho, pro comp and skyjacker make them too i about to drop the blocks and go to high arc skyjacker springs and throw that add a leaf on top