93 2.5 5 speed idle issue

[Chi-town]

I have an issue with my idle flaring from 1500-2000rpm when I open the throttle standing still or when I push in the clutch while driving.

If I down shift and bring the rpm down near 1000rpm before pushing in the clutch it will idle normally.

While sitting still if the idle is flaring and the fans kick on the idle returns to normal.

The idle valve is a brand new VDO unit, I have checked for vacuum leaks and replaced all hoses. There throttle position sensor reads correctly with my scan tool.

I'm at a loss here, anyone have any ideas?

[hybridowner]

My guess is you are driving in a location at higher altitude (above 6000 to 7000 ft elevation) when this is happening. There is a thread on the yahoo Eurovan group regarding this issue for 95 EVCs 2.5L 5 speed manual. Seems to be a problem with the 2.5L 5 spd only. I found other threads regarding this same problem, but none that ever resolved it.

[tds3pete]

Could be a sticky throttle valve. When it is high idling, have you trip tapping the gas pedal one time quickly and hard? If the throttle valve sticks, that will release it.
_________________
'58 Westy camper-come and gone
'73 Westy-bought new in Holland,now gone
'86 Syncro weekender-come and gone
'79 Westy...Oscar
'95 Eurovan Camper/5 spd...Marsha Mellow

[hybridowner]

Here is the best troubleshooting coverage of this problem that I've found:
https://www.justanswer.com/vw-volkswagen/8pmjp-vol...motor.html

Also check yahoo group and you'll find additional discussions there relating to 95 EVC 2.5L 5 spd manual.

[Chi-town]

Ok, so I left Flagstaff (elevation 7000ft) and retuned to Socal (sea level) and my idle issue has disappeared.

I do believe it's an elevation based issue but am unsure if there ecu has a separate internal atmospheric pressure sensor or just the MAP sensor?