I Have a 1997 F150 with 4.2 v6 171,000mi The check Engine light goes on and off saying my intake butterfy is stuck open the garage took the manafold off and cleaned it out on 08/2006, and after a long trip when I come to a stop with vehicle in drive and foot on brake the oil pressure guage goes up and down and the low oil pressure light comes on. If I put ot in Neutral or Park the pressure returns to normal. The Oil was changed 500 miles ago, new pcv valve, oil pressure sensor, oil pump & both new oxygen sensors. Any ideas would be appreciated. Thank you.