maxima 2000 : Engine starting on cold start

I have this strange problem with maxima 2000 SE. On a cold start the engine runs smoothly for a few seconds, then it becomes rough (I can see the engine shaking) and loses power and sometimes it just dies. The shaking lasts only for a few seconds. On starting again (or if it recovers from the rough ride) it stabilises and then it is smooth. Also (Iam not sure whether this a separate problem) for about the first ten minutes of driving the acceleartion is poor. :frown:

Try new plugs/wires?

...the first ten minutes of driving the acceleartion is poor.

One source for cold problems is Throttle Position Sensor TPS. Its used only while cold, during about first 5minutes. After warmup, only A/T uses TPS and engine fuel ctrl starts to use O2 sensor(s) as input.

"runs smoothly for a few seconds, then it becomes rough..."
- MAF's to 2k maxima are told to fail often... test by taking connector off (if MAF is the problem source, this should make a difference).

The PCM uses the TPS 100% of the time..

what is PCM? ...Nissan doesnt have any.

FSM tells the issue like this:

Cold engine =Open Loop, ECU (or ECM) adjusts fuel injection based on TPS, rpm, MAF inputs (not O2).
Warm engine =Closed Loop, ECU adjusts fuel injection based on rpm, MAF, O2 (not TPS)

O2 in the exhaust is the sensor(s) giving feedback how successful the actual latest burning process was (the adjustment 'loop' is closed). O2 sensor is technically very poor - doesnt work well on cold exhaust, this is why its not used cold.

A/T uses TPS input always.

I am thnking of investion in a OBD II scanner/pc adapter. Does anyone hae any ideas on which one buy?

check codes this site tells you howwithout a scanner
http://www.auto-diagnostic-codes.com/