Nissan Repair Questions? Ask a Mechanic for Answers ASAP
Hi there. I just logged in and saw your posting. Unfortunately, all I can see from you at my end is:
"im ready for the answer. the page said the mechanic was waiting for me to pay. I paid and I am waiting"
Would you please elaborate on what it is you need our help with?
Thank you for that information.
Are there any trouble codes in the PCM's memory? Do you have access to a scan tool capable of reading engine data?
OK. I see that you had a smoke test done, which makes me believe there are no vacuum leaks, correct? If so, the issue might be related to valve adjustment or engine timing. Have you checked either one of those? Any possibility of you getting access to a scan tool that can show us sensor values?
I really hate to speculate (which to me is the same as guess), but timing affects intake pressure, which affects MAP signal, which affects injector on-time, which affects O2 signals, which affect idle quality, etc., etc. Valves being misadjusted would have similar effects, so would EGR operation, restricted exhaust, and so on.
Back to the issue at hand; trying to diagnose this issue by symptom only is quite impossible. I would need to know whatever data the sensors are sending over to the computer and then see what the computer is doing in response to that data.
My advice at this point is to start with the basics; set timing and adjust valves, then measure vacuum to see if it is between 18-22"Hg at idle. If not, check exhaust for restrictions. If OK, check EGR valve operation.