I have a 1998 volvo s70 that misfires at 3000rpm, code comes up and check engine light blinks. I had the plugs, wires and injectors checked all are fine. Also had a compression test and all was good there, I replaced the oxygen sensor. what could it be? NOT A VALVE JOB RIGHT?

compression test came out fine 123 on one and 140 on the rest. I'm stummpped

Check 2 things first, the cap and rotor, and fuel pressure. The blinking CEL is usually only thrown because of multiple misfire. Pull the plugs and check the color and gap. The gap should be close to .028 if they are copper. The NA engine uses the 3 prong plugs which are harder to check.

Have you had the timing belt changed recently? If so, rotate the engine and try lining up all 3 timing marks. It is possible that whoever changed the belt didn't align it properly and is off a tooth or two.

Klaus
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Proud owner of a 220S. If I had more room, I would have more Volvos.

Timing belt was done a year and a half ago, I will check the plugs rotor and cap next. Could it be the coil?

Your 1999 should have 5 coils. Have you pulled the codes yet?

Klaus
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Proud owner of a 220S. If I had more room, I would have more Volvos.

yes the code is p0305 misfire #5

Then it is probably just a bad coil. If you want to verify it, swap the coil with #4 and see if the code jumps to P0304.

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Proud owner of a 220S. If I had more room, I would have more Volvos.

this is the coil for my car

http://www.partsgeek.com/catalog/1998/volvo/s70/engine_electrical/ignition_coil.html

Only if you have a 1998. I single coil for 5 cylinders will not pick on one cylinder to fail. Either a plug went bad, a plug wire, the cap, or injector.
Or a valve died, in which case you will need to get a compression test.

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Proud owner of a 220S. If I had more room, I would have more Volvos.

Well the story only gets better, the shop replaced the oxygen sensor and Air mass meter, they did a compression test that came up with the following, #1 cylinder 120lbs and rest 135lbs. misfire in #5. He called a Volvo expert and he said that these cars don't get more then 200K out of them and the #5 valve must be bad. that would cost 2K.My s70 has 256K on it. I brought the car home and based on your suggestion bought new plugs, rotor, cap, and wires. I started buy replacing the rotor because I had not done that in 2 years, put the old plugs back in, in a different order and took it for a spin, check engine light came back on. I took a reading and got a code p0301, well would you believe it was a $2 spark plug. So I replaced all spark plugs and the car runs fine. THANK YOU.......I will be heading back to the garage tomorrow to discuss the $890 i paid to resolve nothing. Now I have a big oil leak in the rear of the motor, I think I might have to clean the PCV system, any suggestions?


Thanks sooooo much

Peter

Next time you buy plugs, opt for the Volvo brand, they usually get over 50K miles and are more reliable. And, yes, plugs can be defective.

As for the AMM and O2 sensor, lots of luck getting some money back!

All compression readings must be done on a warm engine. For NA engines, 185-213psi. Turbo compression, 156-185. All cylinders should be within 10% of each other. So I do not under stand your readings of 120 and 135, those are much too low.

Do a search for replacing the PCV system, it has been posted multiple times.

Klaus
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Proud owner of a 220S. If I had more room, I would have more Volvos.