Stuttering, CEL, not the MAF.

[itsover954]

I recently started having a bit of a stutter in the low rpms of my 98 EB. I then got a CEL and scanned to find P0171 and P0174 codes. I proceded to spray the Maf with electrical cleaner, but to no avail. It actually ran worse. I then went and got a new Maf, but still no dice. What should I be replacing or checking? Thanks in advance for the help.

 

[itsover954]

Replaced Maf still the same. Went and replaced the fuel filter, still the same but different codes.

P1131
and
P1151

Manufacturer control.
fuel air metering.

Anyone?

Pvc changed still stutters.

 

[jlotruglio]

I have been having the same problem, When I changed the fuel filter I had no change. I have a post under power-train with no replies I am looking for a vacuum leak as well.

 

[green03]

P1131 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 1
P1151 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 2

Check for vacuum leaks or any air being drawn into the engine bypassing the mass air meter.

Matt

 

[itsover954]

Just found a leak on a elbow on the PVC vacuum line, still hear a little hiss. Hard to track down because my exhaust is loud. Anyone know how to use hose vacuum hand pumps to find them?

 

[JUST4FUN]

you could take it to a shop and have it smoke tested

 

[itsover954]

How much does that run?

 

[mustangswan]

try looking at the back of the throttle body neck/elbow. it is hard to see, but is very common for those to go bad(pcv hose), our dealership normally stocks each type of pvc hose assembly. A common question they will ask is if the hose is heated or not. on some applications that have a second hose that attaches to the passenger side of the throttle body elbow, there are 2 small coolant lines. That is heated. Hope this helps.