Multiple misfires cylinders 1&3 98 s70 t5

[coop]

Noticed last week the car was dropping idle when coming to a stop. Say would drop to 600rpm then correct itself. Switched out the maf from my parts car to clean the one in there and was pretty good for 2-3 days.
Changed the oil and then took it on the highway when I got a blinking cel notifying me of some misfires.

I replaced the plugs/wires/caps when I bought the car 6-8 months ago. The plugs seemed to be pretty rough and the wires I bought are already coming apart with the boots etc. but went to auto zone replaced the plugs and swapped out back to some Oem wires from the other car and still having the same issues.

This is what I came up with a scan

EF: 121: Mass Air Flow (MAF) sensor signal.
EF: 442: Pulsed secondary air injection system signal faulty
EFI 446: Pulsed secondary air injection system valve leakage
EFl 451: Mistre cylinder 1
EFL 453: Misfire cylinder 3
EFI 543: Misfire exhaust value of at least one cylinder
EFI- 545: Misfire, at least 1 cylinder
EFI-551: Misfire, cylinder 1
EFL 553: Misfire, cylinder 3
EFI-611: Tank system, large leakage. Pressure in fuel tank does not drop

Any ideas?

[scot850]

When you swapped out the MAF, did you clean the connector? They can get pretty corroded. Use contact cleaner and an old tooth brush.
Did you try cleaning the MAF with MAF (only) cleaner?

For testing purposes, what happens if yo do not connect the MAF. Does the car still run or not start?

Neil

[coop]

I have not got in there with contact cleaner yet just some dust off that I had handy.

No difference with the maf unplugged.

The car still runs. Shakes at idle. Feels low on power but at 30mph or so feels better.

[scot850]

I would suggest the next thing to check is have the cylinder compressions checked. This is to eliminate the possibility of burnt valves.

If that turns out to be normal then we need to think again.

Have you checked the crankcase pressure with the latex glove over the oil filler hole?

Have you checked for oil leaking into the distributor?

Neil.

[coop]

Thanks. I’ll check into those today.

It is due for a pcv overhaul. When I brought it to a Volvo mechanic over the summer they noticed it was leaking from the crankcase.

There was a little bit of oil under the valve cover but I haven’t noticed any other issues like smoke from the dipstick or the smell my other car made when it was bad.

The engine has 200xxx miles on it so I’m sure internally it looks great.

[coop]

I tried searching the problem on the forums too and see a bunch of people who had similar issues but no ones really resolved it.

But from what I can gather it’s a burnt up or broken valve that needs attention so I’ll keep that in mind when checking everything.

[foggydogg]

Multiple cylinder misfire can be caused by a vacuum leak, so check the Usual Suspects.
Our turbo cars all tend to like OEM plug wires, and can be sensitive to any plugs other than blue box.

[coop]

I replaced the cam seals and rotor/cap plugs and wires back in the spring. All Bosch/oem stuff. And have been replacing a bunch of hoses so don’t think it’s really a vacuum leak since it holds a steady idle. So might be a slight problem still but wouldn’t be causing the issues I’m seeing.

Is it worth buying a cheap boroscope/camera to inspect the head before taking it off?

I’ve got a 97 850n/a I’ve been using for parts. From what I understand the head is the same but the exhaust valves on the turbo are a heavy dutier version. Can I I use the n/a head temporarily while I rebuild the turbo one? I only ask because these cars are relatively common and rust free around here so it’s almost cheaper to buy another one then do certain jobs when they come up so have been looking for another car or engine to swap for cheap. But I’ve got the parts there and it’s only going to cost me time and frustration lol.