300zx engine problems

[kmm300]

Okay so I got my 300zx a week ago and noticed that my engine will start to sputter and become weak after about 45min of driving. It will lose acceleration and if I try to go faster during this it will basically just stop moving forward. It runs perfectly fine before that. It takes around 5 seconds of cranking to start it sometimes so I am thinking it might be the spark plugs? Anyone had this problem before? thanks

Also, someone said they strongly believe it is the CAS. Anyone know if this is valid?

1991 N/A 300zx

[evildky]

Check the ecu for codes. The cas should throw a code when it fails, granted ecu's do not always throw the codes they should. This particular symptom makes me suspect the CTS, when it goes the car goes very rich, this is fine for cold starts but once warm can actually run so rich it can stall the car then you have to burn off all the excess fuel before it will restart. Be sure you check these and any other connections you can get to, sometimes a bit of moisture in in connector can cause all sorts of gremlins.

[Ace2cool]

^Dave nailed what I was gonna suggest. I'd bet the sensor is going bad OR there's excess corrosion on the connector.

[icemaninlv]

would the CTS going out make it run like crap to about 3k then run great?

[evildky]

CTS causes hard warm starts and can cause the car to run so rich it does, with increased RPM the engine can more easily digest the extra fuel. Rpm related issues usually tied to the MAS, TPS or ECU. Does the car start better when cold? More difficult to start when warm? If so CTS. If it acts the same warm or cold the likely not the CTS. I'd start by checking the connections at both the CTS and the MAS. Next I'd ohm the CTS. Could also be the CAS flaking out.