Rough idling, vibration, jolting acceleration - 98 S70

[hamhead]

I have a New Years resolution to do some self-education on my 98 S70 followed by paying it some much needed attention. I long for the day when I drove her off the sales lot and she zipped around town with acceleration and ease. In hopes of taking a more methodical approach I'm wondering if some in the community here can help with diagnosis and prioritization. At the very bottom I've provided the repair history. Now for the symptoms:

• Overall sluggishness. No ziptang

• I feel a slight vibration coming through the steering wheel when driving. More pronounced when idling. To my ears the engine sounds fine

• There's an awkward jolt if I'm coasting anywhere from 5mph to 25mph and I depress the gas pedal

I have plenty of woodworking but no automotive/mechanical tools of any substance though I just bought some RhinoRamps and a creeper. Advance Auto Parts provided the below codes after a quick scan:

• P0455 – Evaporative emission (EVAP) system -large leak detected

• P0410 – Secondary air injection (AIR) system -malfunction

• P0300 – Random/multiple cylinder(s) -misfire detected

• P0304 – Cylinder 4 -misfire detected

• P0171 – Fuel trim (FT) system too lean, bank 1

• P0172 – System too rich, bank 1 (System too rich, bank 1)

I read and then performed the PCV latex glove test. The glove slowly inflated. After some strategic lurking on this forum and going through the manual I've taken a stab at a potential plan of attack. I'm clueless on how to even start on #2 - #6, but expect I'll find some tutorial(s) on the site for guidance. What am I missing? What's my lowest hanging fruit? What should be my 1st two items?

1. Use a flashlight and some carb cleaner to try and find vacuum leaks
2. Change out spark plugs
3. Volvo Manual says I'm due for a timing belt
4. Check fuel injectors
5. Check fuel pressure
6. Clean out PCV system

Date Mileage Work
6/16/05 66,383 4 new tires
3/17/06 69,643 Test ign and injectors - replace air mass meter
12/11/06 77,783 New windshield
12/21/07 88,057 Replace outer cv boots
3/20/08 91,301 Replace water pump
3/20/08 91,302 Replace brakes - front rotors and pads
1/15/09 99,922 Replace drive axle, input shaft & engine rear main seals
7/22/09 106,857 Replace A/C pressure switch
7/22/09 106,857 Replace control arm on lower ball joint
10/14/09 Install ABS sensor
10/14/09 Replace window switch panel
4/6/10 110,480 Rotors, pads, brakleen & A/C kit
4/8/11 115,069 Replace thermostat, new hose, bleed cooling system
9/26/12 118,253 Replace driver front control arm & drive belt
4/4/13 121,673 Replace plugs, battery, alt, rotor, cap
4/4/13 121,673 Oil trap, crankcase vent hoses, intake manifold gasket
8/27/13 124,275 Replace rear brakes & turbo coolant hose
12/29/15 Left axle assembly, front link rods & strut assembly
12/29/15 Spring seat, front brake hose & link rods, blower motor resistor
12/29/15 Front hub assembly, engine mount, blower motor
12/29/15 135,139 Replace headlight & left axle shaft assemblies

[abscate]

You do want to relive that PCV pressure ASAP. Pressure will blow the cam seals or worse, the engine rear main seal

[sleddriver]

I'd recommend a read of my big thread released several months ago. You'll find lots of good info on there.

Build yourself a smoker to find vac leaks. It'll save you massive amounts of time!

[rspi]

Figure out why it's misfiring first. If the head is damaged, you need to decide what you're going to do about that before you spend money on anything else.

[charleskennedy23]

+1 what Robert said...
- PCV is next
- timing belt after that, however I find it odd that you would change the water pump and not have the timing belt done then as well...
- vibration is probably motor mounts... there are five. Robert has a great video on their location.
- to clear the sas error you could do the sas delete mod if your state allows it.
- stage 0 from there...
- keep car at stage 0 by keeping fluids (oil, transmission, brake, coolant, and power steering) fresh and replacing parts that wear out after a reasonable service life instead of when they break.

That would be my course of action...

[erikv11]

First two items for me would be:
(1) spark plugs
(2) vacuum leaks (the rubber elbow on the passenger side of the intake manifold is missing or crumbled ino oblivion and giving the P0172 - have look!)

But for (1) don't stop there ... When the cap and rotor were replaced two years ago, did they use Bosch items? If those were cheap aftermarket items, they should be replaced as well. If they were Bosch, then they are fine. Your maintenance history shows no evidence of the spark plug wires ever being changed. If this is true (and you can check your wires for the date code to find out), then change those too. My bet is the fersh set of ignition parts will eliminate most or all of the misfires. An MVS member is selling almost-new cap, rotor and wires right now in the classified ads on this site, check it out. I would invest the $75 to make sure it can run properly, then move on to the other repairs including PCV.

Then (3) PCV and the vacuum leaks can also be done at the same time.

Then (4) timing belt.

The vibration will most likely be what is called the front motor mount, it is located below the timing belt, visible through the passenger side front wheel well. Take off the tire first.

Fuel injectors and fuel pressure are not likely an issue unless other troubleshooting brings them to the fore.

[hamhead]

Excellent, thanks. Thinking about your feedback. I think my challenge is to figure out whether this is a lost cause before making a smoker. Below is what I took from your thoughts:

* Watch video on motor mounts

* Ascertain cause of misfiring
* Change out plugs
* Check date and brand of plug wires, cap & rotor. Replace accordingly
* Check compression and fuel pressure

* Check for vacuum leaks
* Build smoke tester and use
* Pay special attention to passenger side intake manifold

* Address PCV system
* Check motor mounts for cause of vibration


I forgot to add that after a minute or two of driving there's a little bit of sweet smell. Not strong though and doesn't last. Can't be good news.

[erikv11]

Looks like a good summary.

The sweet smell is probably a slow leak in the heater core. You'll want to change that before it becomes a fast leak.

[hamhead]

want to give an update (have made progress) and get your take on other issues that have arisen. Not sure if I should start a new thread when introducing a new issue?

Since my last post I've:

- Put in new plugs
- Drained the anti-freeze and replaced the heater core
- Switched over to synthetic Mobil 5W 30 and new oil filter
- Installed a new battery (other one died)

The car seems to have more pep but it stutters and almost stalls completely right as I come to stop at a light. Good news is after taking these steps my only code is 0118 (Engine Coolant Temperature Sensor Circuit High Input). This surfaced right about the same time I put in the new battery which seems to have upset the car.

Frequently now when I turn the key I just hear a click followed by strange electrical happenings involving dash lights, seatbelt alarms and door locks. After waiting 15 minutes to a couple of hours it will start.

My smoke testing skills need improving. Mine kept falling apart. I found no leaks for what it's worth. Where do I insert the tube for blowing the smoke? I'd seen where Robert DIY used one of the nipples on the vacuum tree which is what I did. Do I have to block anything off for this to work?

one thing I noticed when changing the oil was an unattached tube hanging out at the bottom front right corner. I took a picture and attached it.

Below are some indicators I pulled from my android app that are over my head but may mean something to you:

Turbo boost and vacuum - psi: 15 - 20 fluctuation
Vacuum:
MAF g/s: 4.4
Timing Adv: 8.0
Coolant - Fahrenheit: 260 degrees
Throttle position (manifold): 11%
Fuel bank trim - short term: 25.0

To summarize:

- Code 0118
- Engine fan runs every time car stops for about 5 minutes
- 50% of time car just clicks when key is turned.
- Car shudders and almost stalls when coming to a stop
- a small tube as round as a pixie stick is hanging out unattached

Thoughts?

[chrafael]

Change coolant temp sensor by thermostat and check connector, inspect all battery cable connections for looseness, corrosion. Then recheck for codes.