1989 mazda mpv 18 valve v 6 when it starts it surges, if you drive it, it will drop in rpms to 500 to 1000 if you give it gas it will bogg out but if you let off the gas or put it in nutral it will bunce back up to 1200 rpms. after it runs for about 5 minitues the rad will begin to boil... i have put in new therostate and water pump. there is no air bubles in the rad and fluid is flowing threw the engine...i think... white smok in the exaust. and it smells like gas..thought there might be water in the gas..put in fuel additive..no change..also put in injector cleaner..no change...i am wondering now could it be a sensor?? it is not a cracked head or blown gasket because there is no water in the oil. however there is oil in the rad..after a rad flush there is no oil in the rad anymore...i am so confused... this is our only vehicle and we can not afford to bring it in to a shop... any help would be great thank you in advance..dave

 

did you ever get it fixed? mines doing the same thing.