Service Engine Light 98 chevy Lumina

My 98 chevy luminas service engine light came on after I got gas. I put vaseline around the threads to seal it and the light went out for 2 days and then came on again. I bought a new cap and the same thing happened, two days light out than back on. I took the car to Autozone and did a diagnostics test which came back with error message P0341, then took it a mechanic who ran his on diagnostics on it and he says the camshaft sensor needs changed. It is a semi expensive job for an older car and I want to be sure that that is the problem, plus the gas cap thing has me confused. any help would be appreciated. Thanks in advance.

PO341 is camshaft sensor range incorrect, yes. If there were no codes for the evap emissions system, the gas cap had nothing to do with the CEL.

Another thing to remember is that the PCM is only reporting what it is detecting. The trouble code P0341 is not defined as "CMP Needs to be Replaced." Someone is perhaps misinterpreting the data. Instead, the code is described as "Camshaft Position Sensor Range or Performance Malfunction." All the PCM can detect is that the signal is not consistent. That can be caused by several things including, but not limited to, the CMP sensor. If you trust that your mechanic has already performed a complete diagnosis and has correctly determined that the sensor itself is the problem, then you can confidently authorize the repair. If, however, you suspect that the signal has not been tested directly at the sensor, the wire harness has not been inspected, and that the CMP sensor is receiving correct supply voltage and ground, I can understand your hesitation.

Actually, replacing the CMP is not that difficult on a 3.1/3.4 V-6. The accessories are in the way, and may have to be removed, but the work is not difficult. The other problem is that the camshaft itself can also have an influence on signal generation, since the "target" for the sensor is on the camshaft front journal. Contamination of the sensor is frequently a problem, and simply cleaning it can sometimes restore sensor performance. A camshaft which is "walking" in the block due to a worn thrust plate or cam sprocket can also affect signal. A worn timing chain can affect signal consistency (performance).

If the sensor has been tested and is failing electrically, however, there is little to do but replace it.

I agree with Blue. The serp belt and power steering pump will have to be removed, then the CMPS is right there (on the 3100). One bolt securing it to the engine block and a wiring harness. If your car has the 3800, the CMPS is in the timing cover (relatively simple to change) but it could also be the interrupter magnet in the cam gear that is causing this code. Replacing it requires the timing cover and cam gear to be removed from the engine, which is a major repair.

Regarding 1998 Lumina P0341 code. Started seeing code P0341 repetitively. I would reset the codes but it would come back after a few minutes. At or near the same time, I was experiencing occasional dead battery problems. I installed a new battery and reset the code. The code did not re-appear for 3 months until an interior light was left on over an extended period without driving the vehicle. I jump started the car and found the P0341 code started appearing again. I charged the battery and reset the code, drove the car for 50 miles with no new codes. I just had the car pass California's smog inspection with flying colors. My conclusion: Make sure you have a properly working electrical charging system and a good battery before throwing parts at the car based on any codes reported by the ECM alone.

Good info but this thread has been dead for 7 years!

A thread is only truly dead when no one bothers to read it. I see you read it.
I believe that many readers are looking for information without posting a reply.
:sarcasmsign:

A thread is only truly dead when no one bothers to read it. I see you read it.
I believe that many readers are looking for information without posting a reply.
:sarcasmsign: A new thread would draw much more attention to the issue, this is the format we try and adhere to. I read because as a moderator I try and monitor the traffic.