Check out some similar questions!

deltadog74 · Mar 30, 2009, 08:57 AM

hi this is my first post. I have been trying to find an answer all over and hopefully someone here can help! I have a99 chevy tahoe 4x4 and the code for my camsensor came up. I have changed the sensor and still have the same code. It misses at highway speeds (not continually most when I go up a hill or something). I had the same thing happen to my 02 s10 and I changed the whole distributor and solved that problem, my question is do I need to change the distributor in my tahoe or just pull it and drop the same dist in? If I can avoid changing the dist. I would obviously like it more! Thanks kyle

TxGreaseMonkey · Mar 30, 2009, 09:06 AM

Did you reset the ECM afterwards? If not, try disconnecting the negative battery cable for 15 seconds.

deltadog74 · Mar 30, 2009, 09:36 AM

Hi yes I reste the computer, I have a autozone bought scan tool, and when I rest it it will go off until start it up again, then the same thing happens.

CaptainRich · Mar 30, 2009, 07:21 PM

What is the actual code that is being stored? Are there any other symptoms other than misfiring on the highway and under load?

deltadog74 · Mar 31, 2009, 06:01 AM

No that's about it. There's no rough idle and runs fine around town but when I get to about 65 it starts missing.

deltadog74 · Apr 1, 2009, 06:09 AM

The code is po 340.
I pulled the distributor last night and found some silicone at the bottom of the distributr just above the gear. When some one put it in the silicone for the intake must mave been still wet. So I took it off. Now mind you that when I pulled it out I did not take the cap or rotor off just the whole thing. I did turn the gear but never turned the motor (crankshaft)
Now it is acting like it is out of time, backfiring, rough idle will barely run if at all. Did I get it out of time by turning the distributr gear therefor moving the rotor and screwing up the timing? If so is there an easier way to fix this problem without having to bring the #1 to tdc and setting time like that? Agggh, please help!

CaptainRich · Apr 2, 2009, 08:16 AM

It does sound to me like you've gotten it severely out of time.
The only way is to set the engine #1 to TDC and index the distributor properly.

First, the P0340 is for the sensor circuit. The sensor may be working fine but it's signal isn't getting to the Engine Control Module (ECM), or the ECM cannot read the info.

Secondly, the miss at highway speed may be a weak coil or it could be starving for fuel at the higher speed.

More diagnostic information will be needed. If you could access sensor data during the misfire event, you could rule out several things.

deltadog74 · Apr 2, 2009, 08:44 AM

Hey man, thanks for the info! The fuel gauge is fluttering and showing full all the time (if it was only really full I wouldn't worry!) I figured I need to change the pump/sending unit to solve this. Could this be part of my miss? As for the 340 code what would cause the signal not reaching the pcm if not the sensor itself? I checked the wires leading from the sensor and there is no binding/cut or burned wires.

CaptainRich · Apr 5, 2009, 08:14 PM

For the engine code, scan data would be critical at this point. I need to know what issue is causing that code to set.

Certainly, if you're already having a concern with the fuel sender and/or fuel pump, that would be the very next thing you'd do, if supported be additional diagnotsics.