kinglenario

hi, i wanted to post some symptoms i'm having with my 1986 951.

first of all i just changed the oil last week to amsoil 20w50 Zmax, extra zinc ZDDP for older cars and cars with flat tappet cams. everything seemed to run quieter and better oil pressure than before in the hot summer weather of atlanta.

yesterday on the way home from work i got on it a little bit and my RPMs didn't want to come back down. it would just hang from 2000 to 1500 and came down VERY slowly. while idling high it smelled and looked like it was running rich.

then when i started it up today it sounded like there was an exhaust leak but the sound went away after running for about 1 minute.

i drove it to work, and when i started it back up again i heard what sounded like a one cylinder exhaust leak again (thip, thip, thip, thip, thip). so i quickly popped the hood and it sounded like tapping at that point so i really don't know what it is. again it went away after about 1 minute.

could this be some sort of sensor? the temp sensor in the AFM perhaps? i'm planning on cleaning the ICV, changing the Idle sensor switch, and changing all the vacuum lines this weekend.

if anyone has some better input as to what i should check that would be great. i'm new to maintenance and troubleshooting on these. i'm hoping it's not something in the engine internals causing it.

thanks!

kinglenario

UPDATE: ok, on the cold start this morning i tried to inspect more closely. the noise is coming from hear the valve train from the cylinder closest to the firewall (cyl 4). it sounds like lifter noise but could be a header leak or injector noise. it sounds like loud tapping you can hear from the drivers seat with the door open.

again, it goes away after about 1 minute and doesn't do it again.

as i said i changed the oil from 5w30 to 20w50 amsoil with a porsche filter a few days ago and the noise started a few days after i changed it. the 20w50 made the oil pressure much better and my pressure is running full 5 bars when cold and a little above 2 bars when really hot at idle.

i'm new to working on this car so any input and ideas of what to check for would be greatly appreciated.

thanks

kinglenario

anybody? please!!! some insight. loud ticking during startup for about 1 minute. around cylinder 4. even when i only turn the car off for about an hour or so. i also smelled a little rich exhaust this last time. what should i look for here?