Engine loses power when cold

[1-3-2-4]

This has just started up but I thought it was me just slow shifting so with the car running for about a min I backed out got up to 2nd gear and around 2500 the car just like lost power and the funny thing is it only happens once! and only when cold...

But go figure I finally got the CEL to come on.. but anyone know before I get home and bring out the code reader that would be helpful

ok I'm home and I scanned the code.. and kinda what I thought..

the O2 sensor 1 Bank 1 says malfunction and had another pending code for the same one..

I thought the 02 sensor was not used until the car warmed up?

[Huffer]

The car runs in open loop until it warms up but I believe that only means the ecu doesn't pick up a reading from the rear o2. The cel you have indicates front o2.

[Sarra]

The car times how long the O2 takes to function. If it takes too long, it flags a code. Is it a heater code, or an actual O2 code?

[1-3-2-4]

That I remember o2 code.. I have to wait 3 times before it shows another CEL. It looks like the one that came with the car..

[1-3-2-4]

code came back during a drive to the bank

P0130

o2 Sensor circuit malfunction (bank 1 sensor 1)

the voltages was all over the place but a screen grab which I think is the first o2 sensor is:

At 2K RPM

o2S11

1.030 V

o2S12

V 0.055


Idle

O2S11

0.910V -7.0 %

o2s12

0.030

0.0%

[Huffer]

Looks like the front O2 is on it's way out.

[Sarra]

The front O2 SHOULD go from under 200 millivolts (.2v) to over 800 millivolts (.8 volts).

You'll need an OScope to properly test it, since it takes milliseconds for it to go from high to low, and if it is slow, you can't actually see that on a tool (Class II data bus isn't fast enough).

[1-3-2-4]

The front O2 SHOULD go from under 200 millivolts (.2v) to over 800 millivolts (.8 volts).

You'll need an OScope to properly test it, since it takes milliseconds for it to go from high to low, and if it is slow, you can't actually see that on a tool (Class II data bus isn't fast enough).

yeah well Santa is not getting me a Oscope until Christmas so I can't wait.

so are you saying that it's reading to high at idle?

[Sarra]

I can't tell... Do you have a multimeter? You can set one to show you a min and max peak range, hook it up to the O2 sensor wires, let it idle for a little bit, and that should give you a somewhat more clear answer.

Also, might idle a little lean, give it a little gas, should go straight to 1v when you rev it, and drop back to around 0v-0.2v as the revs drop (tip in enrichment on rev = no oxygen in the exhaust, dropping to idle = tons of oxygen in the exhaust).

[1-3-2-4]

lol I build and repair circuits I'd never go without a multimeter.. but I will test.. right now it's nasty weather out but I got to thinking that this sensor was telling on it's self before the CEL came on..

before all of this:

Car cold and start up.. does it's warmup stuff and idles around 750


after driving some time to warm the car up and say you had to get gas or stop in the food store you start the car and this is how my tach looked..

1000-500-750

[Sarra]

lol I build and repair circuits I'd never go without a multimeter.. but I will test.. right now it's nasty weather out but I got to thinking that this sensor was telling on it's self before the CEL came on..

before all of this:

Car cold and start up.. does it's warmup stuff and idles around 750


after driving some time to warm the car up and say you had to get gas or stop in the food store you start the car and this is how my tach looked..

1000-500-750

If it's dipping below idle then coming back up to normal idle from higher revs, that's either IAC or throttle. You need to clean the IAC and probably the throttle plate.

[ccampbell2546]

I've been experiencing the same problem with my car. If I don't let it warm up long enough I'll lose power under 3k rpms. I do have two CEL codes for a circuit malfunction in both the front and rear O2 sensors too. Is there any connection between the power loss and the O2 codes?

[Sarra]

I've been experiencing the same problem with my car. If I don't let it warm up long enough I'll lose power under 3k rpms. I do have two CEL codes for a circuit malfunction in both the front and rear O2 sensors too. Is there any connection between the power loss and the O2 codes?

Yeah, it's probably running retarded rich. :lol:

[1-3-2-4]

I wanted to update.. So I've been driving for about 5 days with no CEL and now I'm starting to think it's a leaky injector when the car is shutoff I'm thinking it's dipping fuel in the cylinder and when I start it that's why it runs a little rough until it's burned off..

however how do I go about checking which injector it is? but given the cars age I don't know if they have been changed before? How often are they meant to be changed out?

[Huffer]

They get changed out when they don't work. Try running some seafoam or Chevron Techron fuel injector.