2000 pontiac grand am 2.4 ltr 165000 miles. Replaced faulty fuel pump and regulator and sparkplug boots. I have a long crank cycle at start but once running runs good. Then driving it it just dies, pull over and wait then it restarts. Noticed tach acting eratic and wondering if loosing rpm reference. Could the two problems be related? Quiting while driving is intrmittent. Any ideas would be helpful.