P1151 Question

[98 Contour]

Hello all, this is a great forum, lots of good info!

I have a 98 Contour, 2.5 MTX, 71,000 miles, with a recent tuneup (plugs & wires). CEL is on, throwing a P1151 code. After searching the forum, I've narrowed this to three most-likely possibilities:
-bad bank 2 O2 sensor
-vacuum leak
-possible problem with the IAC valve.

In addition, the car "mooses" in cold weather, and tries to stall when it's been run for a while (usually over 1/2 an hour).

Before I start replacing things, I figured I would ask here to see if this is a common problem or if there is anything else I should be checking. Any help is appreciated. Thanks!

Chris

 

[BrApple]

[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]

time for a new sensor

for the moose you can change the IAC, make sure its a OEM one

http://www.contour.org/FAQ/FAQ.php?s=probs&displayid=15

http://www.contour.org/FAQ/FAQ.php?s=probs&displayid=3

 

[98 Contour]

Okay, so it looks like I'll have to replace both.
Will replacing the IAC help with the poor warm idle, or is that more related to the bad O2?

Thanks for the fast reply!

Chris

 

[zorrex]

It's probably related to the O2 sensor. The idle kinda drops down when you're sitting at a stop or something, right?

 

[Tony2005]

Okay, so it looks like I'll have to replace both.
Will replacing the IAC help with the poor warm idle, or is that more related to the bad O2?

Thanks for the fast reply!

Chris

Bad Idle Air Control (IAC) Valve = idle issues.
Bad O2 sensor = Bad O2 sensor

 

[zorrex]

Bad Idle Air Control (IAC) Valve = idle issues.
Bad O2 sensor = Bad O2 sensor

But a bad O2 can also cause idle issues. Start with the known problems first, a.k.a. the O2 sensor, and work your way down the list.

 

[98 Contour]

But a bad O2 can also cause idle issues. Start with the known problems first, a.k.a. the O2 sensor, and work your way down the list.

Thanks for the help. I'll see if the O2 sensor fixes the problem.