98 csvt with p0171 p0174 p1131 p1151

[BumpPerformancedotcom]

So I bought this car knowing it had these codes which typically are a result of having some sort of air leak thats by passing the maf and therefore being unmetered and cauing both banks to show lean.

So first thing I did was replace the maf, the previous owner did it 10 months ago and I had it warrantied. Why not? Didnt fix

2ndly I sprayed all around the intake upper, lower, egr etc.
Result : Nothing

So I replaced the intake gaskets because with 102k I figured that be my best bet. All day it ran great and nothing. I also checked the pcv and replace it because it was bad.

Next day codes are back. So I blocked off the egr just to make sure that wasnt sticking open.

I was trying to avoid doing the o2s because it seems like that should be the last step and usually not the cause.

So it either has to be the 02s or injectors correct? The injectors look nearly new and they look like the 19lb explorer injectors so Im leaning towards the o2s

The codes are back p1131 p1151 p0171 p0174

 

[BrApple]

[FONT=arial,verdana,helvetica,sans-serif]P0171 - [/FONT][FONT=arial,verdana,helvetica,sans-serif]System Too Lean - Bank No. 1. [/FONT]

[FONT=arial,verdana,helvetica,sans-serif]P0174 - [/FONT][FONT=arial,verdana,helvetica,sans-serif]System Too Lean - Bank No. 2. [/FONT]

[FONT=arial,verdana,helvetica,sans-serif]P1131 - [/FONT][FONT=arial,verdana,helvetica,sans-serif]Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 1. [/FONT]

[FONT=arial,verdana,helvetica,sans-serif]P1151 - [/FONT][FONT=arial,verdana,helvetica,sans-serif]Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 2. [/FONT]

it could be that the O2 sensors need to be replaced but with all the codes pointing to a lean condition I would have to say its something else.

yes check for vacuum leaks. clean the maf etc

if the egr was stuck open the car would have a very poor idle.

 

[BumpPerformancedotcom]

I was under the same path with my investigation but I really dont know what else to check, egr was ok, i replaced the intake gaskets, maf replaced, checked all vacuum hoses, etc...

 

[SVTGT350]

I would additionally check fuel pressure and volume, possibly restricted fuel filter and clogged injectors. Could be the MAF isn't correct for the injectors, ie. MAF calibrated for 17 lbs. injectors and you are running 19 lbs.

 

[BumpPerformancedotcom]

I would additionally check fuel pressure and volume, possibly restricted fuel filter and clogged injectors. Could be the MAF isn't correct for the injectors, ie. MAF calibrated for 17 lbs. injectors and you are running 19 lbs.

then it would run rich, the maf already has been replaced. Im going to o2 sensors when i do my headers.

 

[BumpPerformancedotcom]

Ok intake manifold and imrcs fully cleaned checked for flatness and new gaskets installed, egr checks, tb cleaned, iac checked and i still get the 1131 and 1151 so all i can do is check fuel pressure and replace 02s? i hae a volt meter hooked up and at a cold start and prior to a fully warm engine its working properly but once its warm it seems to stay at a certain voltage for a while before clearing up. any suggestions