Misfires will not go away, 98 S70 GLT

[canyoudig_it]

It's me again, with misfire problems still. Today my car stalled five times in less than a 1/4 mile, and was pumping out some serious white smoke when stumbling along. I have pretty much had the same problem for months now, but the more I repair the worse it all seems to get with time. After new hardware is put on, the car usually drives nice for a day or two, then all hell breaks loose again.

These are the codes my car is giving, they have been the same since day one, and a new one has not yet appeared. P0300, P0302, and P0108. The 03XX codes I understand are misfires, one for cylinder 2 and the other for all cylinders. The 0108 code, I'm unsure, something to do with living in higher elevated areas, but from what I gather it is not related

What have I replaced? Spark plugs, wires, cap, rotor, coil, MAF, some punctured hoses, fuel pump, and fuel filter.

The only parts that are not a cheap replacements are the spark plug wires (Bosch) and the distributor cap (I bought a Replacement brand, but it has Bosch written on it in a few places like the one I replaced). The spark plugs were NGK copper, the ones they replaced were the same brand, not sure how old they were, but my gapping tool couldn't measure the old ones they were so worn down. The rotor, MAF, pump and filter, none were OEM parts, just a cheaper replacement part.

Tomorrow I have some new platinum tipped plugs coming in the mail, I plan on inspecting my current plugs to check for wear, oil or coolant on them. They are only a few months old, but where copper tipped.

I am almost to the point where I want to take it to Volvo and have them diagnose the problem. I cannot believe how much worse the problem is getting with all the parts I have replaced. Two days ago, I took my battery terminal off for a while to reset the computer, it ran rough for a bit and never leveled out after that.

Could this possibly be something as simple as my timing being off? I wonder that since I have replaced the plugs,wires, cap and rotor. The distributor cap was set up a little different then the one I took off, when seated properly the wire connections were protruding out differently. I was sure to match them up the same, however, as the one I took off.

Any possible ideas? Should I give in to a mechanic or dealership and have them look at it?

[binglax09]

Check timing (pop cover off and align the marks)
Compression check!!
Wires NEED to be in the correct spot and Bougicord NOT Bosch
Plugs should ALWAYS be Volvo branded when diagnosing misfire issues
Cap rotor should be bosch but are not as much of an issue most times.

Replace the altitude sensor with a used unit as well, or clean the connection. GOOGLE!

[rspi]

#1 Issues the these cars besides the PCV system is the fuel pump relay. If that is over 7 years old change it. If it's cutting the fuel pump off and on you will have issues.

The rest of my story is there ^.

[rmmagow]

Don't bother with the platinum plugs, Volvo's don't like them. Bosch wires aren't very good either. Volvo plugs from a dealer will set you back about 50 or 60 bucks. The MAF being non-oem could be an issue. The deal about the cap is confusing. It should be exactly the same as the one you replaced.

[jblackburn]

A compression check needs to be done at this point.

[cn90]

As binglax said above,

Misfire is hard to troubleshoot on the internet, but when it comes to the ignition department, most people in this forum would agree that:
- Spark Plugs: Bosch Copper or NGK Copper (or Volvo OEM).
- Cap/Rotor: Bosch only.
- Spark Plug Wires: Bougicord only! Make sure you connect to the proper numbered posts on the cap!
- Ignition Coil: Bosch only. This item rarely fails.

- MAF: Bosch (or Volvo OEM) only, nothing else.

Once you make afresh start with the above list, then trouble-shooting is easier.