Problem Child: 1996 850 base
Last known mileage 186,965

Symptoms:
1. Hard to start have to hold key longer then usual on cold start (starts right up on warm starts)

2. CEL on last time i checked was front o2 sensor, (about to replace)

3. Stumbles at idle when at lights n stops signs (random not always)

4. all lights dim (dash n headlights) when i use my brakes or turn signals.

5. randomly treys to stall n usually kicks out of it when i use brake turn signals or and some times window switches. when it does the abs light comes my all my lights dim n when she kicks out of it all is normal again no abs or lights dimming.

history:i had to let go of our 2013 S60 earlier this year n just had to sell our 04 XC90 due to financial issue thanks to wife being let go n a major cut in hours for me. so with a wife n 3 kids in dire straits money wise i bought this mechanic special 850 for dirt cheap. It looks like hell thanks to some ones spay paint job trying to fix faded n clear coat chipping paint, but it ran fine n drove good, I got it from a fellow Volvo fanatic who is a mechanic and I was told it needed a front 02 sensor and needed a control arm the price was good to good to pass up.

Fast Forward 2 mouths:

Its always been a little hard to start i have to hold the key longer then usual on cold starts. brake light just came on this week, & lately shes been stumbling at lights n signs when in gear, but the tach dosnt move any from where she idles around 900 to 950. wife told me a few days ago lights where dimming when she used the turn signal or window switches & radio would cut out randomly.I didn't think anything of it all my 240 940s & S60s & XC90 did that at one time or another. and thought maybe radio was crapping out as it is the stock one.

Drove the car for a good 3 hours this morning tool & part shopping getting ready for doing the 02 sensor n all control arms n tie rods. Got both control arms replaced,could not get the tie rod ends loose from the inner tie rods. just keep spinning both tie rods half the time heat from a propane torch did not help just stripping the lock nut. going to have to cut them off n replace both inner n outer. also found passenger sway bar end link broken.

Took the car to work this evening and on way home it tried stalling but never died n came back. This happend on highway on-ramp on the, highway doing 55 and at 2 stoplights a 20 mile trip, every time id ether be on brakes or using turn signal or both. when this happens my lights dim and my speddo and tach drop n abs light comes on when she comes back on her own from trying to stall every is normal.

got it home and i did a quick test. put her in park foot on brake n she idles normal at around 900 to 1000 rpm. dropped her in gear with foot on brakes n turn signal on and rolling windows up she stalls with abs light n everything dimming and dies with all dash lights on. put her in park n she starts right up no problem. also i noticed when in any gear drive gear i saw the up triangle come on, n turn off when i put here in normal drive. car was not in winter mode AFAIK n deftly not in sport mode.

any ideas could it be a vacuum leak at the brake booster or throttle body the air mass, the tranny? ive read so many things about random stalling i have no clue lol, any help would be appreciated.

 

for hard cold starts, I'd start by looking at two things: fuel pressure (ie pressure sensor/regulator parts) and engine coolant temp sensor.

O2 sensor CELs may also be signs of a vacuum leak. Check vacuum lines/tree etc. The code may be saying "out of range" meaning the sensor can't compensate for a mixture problem (which may actually be caused by fuel pressure or vacuum/air leaks).

For the dimming lights, what's your battery voltage - engine off, at idle, under load?

low system voltage can cause stalling/stumbling so I'd be looking at the alternator or battery system to start.

MT