A new O2 sensor fixed that problem for me. Easy enough to do if you can break the old one loose but that part was a whole separate job for me, requiring a second vehicle pulling a chain to a bigass wrench on the sensor socket. Popped loose with a satisfying *tink* noise. Anti-seize on the threads of the new one, of course. 

Stephen

Mobile

> On Dec 2, 2022, at 3:27 PM, Dennis Haynes <d23haynes57@hotmail.com> wrote:
> 
> My vote, problem with the O2 Sensor system. Sensor itself or wiring/ECU problem. For confirmation, cycle the ignition off and back on quickly while the symptom is occurring. If the reset clears it for some duration, then you most likely found the cause. Temp sensors and related wiring will usually cause the most grief getting the engine started. 
> Dennis
> 
> 
> -----Original Message-----
> From: Vanagon Mailing List <vanagon@gerry.vanagon.com> On Behalf Of Dan N
> Sent: Friday, December 2, 2022 2:35 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: I need help, please
> 
> hi all,
> 
> I have an '88 tintop (298K miles) van with this problem. It starts fine, idles fine, revs up fine. But recently when it reaches operating temperature it stumbles, almost dying not willing to go up higher rpm. This happens with warm or cold outdoor temperatures.
> Things have been done a few days ago.
> - New dist. cap and rotor
> - NGK BP6ET are recent.
> - Throttle body switch checked fine
> - Idle screw on throttle body cleaned
> - A good fuel pressure regulator was swapped in.
> - Air filter checked.
> - AFM connection checked
> - No vacuum leak on any hose.
> - Idle control valve checked, working fine
> 
> So what happened and what to do next...?
> 
> Thank you for any help...
> 
> dan