I have read through many similar posts but cannot find an answer. I have a 2001 SL2, and about a month ago it started stuttering/chugging when accelerating in drive. It only starts this once the engine is hot, my temp gauge never goes above 1/4 to barely over a 1/4. It idles very rough in gear, barely stays running, in park or neutral it is a little better but still idles very rough.

I replaced the spark plugs, fuel filter and the EGR valve but they had no effect on the situation. The EGR valve was dirty and could not get it free so it got replaced. It seems to be getting progressively worse, I barely made it home today, it chugged the whole time I was driving which was new. My CEL is on as well and when it chugs really bad it starts to flash (not good)I had an ‘02 SL2 that had all the same symptom and it eventually left me stranded and I got rid of it. Any ideas?

Thank you in advance

 

Go get the codes read for free at AutoZone or similar for free

Flashing cel=misfire.

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Codes first.

 

Sorry I forgot to put the codes in the original post.
The codes that came up were

P0340 - cam position sensor - a bank 1 ckt malfunction

P0341 - cam position sensor - A ckt range/perform bnk 1

P0442 - evap system small leak

P0711 - Transmission fluid temp sensor A ckt range/perform

Thanks for any help that you can give.

 

We are missing the misfire code(s).
Have you looked at the cam sensor? Might want to look .at that first.
Trans next
evap can wait

 

There is no actual physical cam position sensor. It's a virtual sensor inferred from the ignition. That code can be caused by ignition problems. SInce you replaced the plugs and assuming they are the recommended copper type I would look at the plug wires. I had a code 341 that was due to a bad #4 wire.

 

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Home >> Saturn >> 2001 >> SL2 L4-1.9L DOHC VIN 7 >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P0340

P0340

Diagnostic Chart:

Schematic:

The electronic ignition (EI) module supplies a ground to the cylinder #4 signal wire whenever it determines cylinder #4 has just fired on its compression stroke. The EI module uses capacitive pickup plates located under the 1/4 coil pack to determine the polarity sequence and voltage amplitude of the cylinder 1/4 secondary ignition. The PCM supplies 5 volts on the signal line and expects to see the cylinder #4 signal wire go low after every 14 crankshaft pulses (2 revolutions). This is used to determine the position of the camshaft, except under decel. The PCM only uses the transition from 5 to 0 volts as a valid TDC compression #4 cylinder signal. DTC P0340 sets when the PCM detects missing cam pulses (not seeing one cam pulse every two crankshaft revolutions).

DTC PARAMETERS
DTC P0340 will set if the PCM cam pulse has not been properly detected (cylinder #4 signal line not pulled to ground) for 136 engine revolutions when MAP is greater than 30 kPa.

If the PCM detects 20 correct cam pulses in a row, DTC P0340 will pass for the rest of the ignition cycle.

DTC P0340 diagnostic runs continuously until 20 correct cam pulses have been received when the vehicle is not in a decel.

DTC P0340 is a type B DTC.

DIAGNOSTIC AIDS
Use Scan tool to monitor CMP RESYNC COUNTER while running engine. The counter should count to 14, which indicates the number of notches passed on the crankshaft in 2 revolutions, then reset to zero when a cam pulse is received.

High resistance in the #1 secondary ignition system or low resistance in the #4 secondary ignition system can set this DTC. Check for corroded or loose #1 or #4 secondary ignition components. Use Scan tool to monitor MISFIRE CURRENT CYL. #1 and #4 which may point out an intermittent misfire causing the DTC.

A missing cam pulse without a cylinder misfire may not affect engine operation.
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