tgreer9768

What are normal readings for the O2 sensors on an Impala??? Or perhaps a better way t to ask the question.... how would you test the to determine if they are defective?

bigrod118

well our cars are smart enough that all the information is feed into the computer and the car will throw a code when things to bad ie O2 sensors, cat, things like that.

what problem are you having

tgreer9768

car intermitantly will die out while driving. Car will be running running fine at a constant speen but all of a sudden the rpms will either jump up high or most of the time drop drasticly. For lack of better wording... the engine will then seem steady out again but sometimes will show a check engine light after the rpms go up or down. Also when this happens when the car hits around 35-38 miles an hours you can hear the engine knocking really bad and there is almost no acceleraction. The knock clears up once the car gets up to about 45-50 mph.

I guess once the car goes through a couple driving cycles the problems goes away for a while... then is will do what i described above.... rise and repeat.

We just had the cat replaced last week for this problem... did not fix it. When we take it to the dealer (4 times) they never can tell us what is wrong with the car. The only code showing up is a crank sensor which they say checks out fine and there some engine knock code.

BNaylor

Which engine do you have - Series II 3800 or 3.4L?

The knock sensor module in the PCM is detecting knock because your crankshaft position sensor (CKPS - one at haramonic balancer) is going South and the timing is being thrown off. The dealer has not properly tested the CKPS because they probably ran it on a Tech II without duplicating your conditions. The only way to properly check the 18X (3800) or 24X (3.4L) pulses is with an ocilloscope. I'd trust the PCM which did throw a CKPS DTC error code. Post the specific odb-ii code if you can.

__________________

'08 Pontiac Grand Prix GXP (Dark Slate Metallic) - LS4 5.3L V8
'08 Pontiac Grand Prix GXP (Liquid Silver Metallic) - LS4 5.3L V8
'02 Oldsmobile Alero GL2 - LA1 3400 V6
'99 Buick Regal LS - L36 Series II 3800 V6
'03 Honda CR250R MX - 2 Stroke 250cc
'97 Pontiac Grand Prix GTP - L67 Series II 3800 V6 Supercharged
Timeslip 08/12/06

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tgreer9768

its has the 3800... I got a chance to get the codes from the car...

p0336 - crank senosr code.... also said something bout 18x

car died out while driving home 3 times yesterday....

BNaylor

The CKPS is a common problem on the Series II 3800. Change it out and you'll be back on the road safely. Here's a procedure that will work although it is for a Grand Prix. The sensor cost ranges from $30 - $50. Good luck!

http://mykidz.net/GTP/CrankPosSensor.shtml

__________________

'08 Pontiac Grand Prix GXP (Dark Slate Metallic) - LS4 5.3L V8
'08 Pontiac Grand Prix GXP (Liquid Silver Metallic) - LS4 5.3L V8
'02 Oldsmobile Alero GL2 - LA1 3400 V6
'99 Buick Regal LS - L36 Series II 3800 V6
'03 Honda CR250R MX - 2 Stroke 250cc
'97 Pontiac Grand Prix GTP - L67 Series II 3800 V6 Supercharged
Timeslip 08/12/06

AF Community Guidelines