My 96 850 turbo with 95k has a misfire. It does not happen all the time, and I can't pin point like conditions when it happens. However, I do a lot of freeway driving and it tends to happen in the evening on the way home freeway speed car has not been drove in 9 hours.

I have put in new plugs (volvo), wires (bogicord), cap and rotor (bosch). I have noticed a vacuum line with a crack in it. It is the vac line that goes from the air intake into the turbo. It does not seem to me like that would cause the misfire.

What I am wondering is what should I check next to try and determine the problem.

 

is your check engine light on? is it throwing any other codes?

 

It is but I can't think of the p code. It says something about a manufacture specific drive train problem.

 

check all your vacuum lines, has the O2 ever been replaced? have you cleaned your MAF at all? what kinda MPG are you getting?

 

Are your plugs gapped correctly?

 

As soon as I saw your post gilber33 I knew you were going to go there

Can we get a little more description of the problem? Are you at a steady speed, accelerating, stopping, slowing, idle? Whats happening when it happens?

 

lol. It seems to be a very important step that a lot of people forget about.

 

Plugs are to spec. Checked each one before I put them in.

To the what's happening when its happening question... I think all of the above. But it is most pronounced going steady at freeway speed. I have definitely noticed it at acceleration, and steady, and I think idle too. (I will try to pay more attention to this).

The MAF I have never cleaned because the fasteners they put on (t-20 I think it is). The peg is larger than the hole on the bit. And I have tried numerous bits. I got to figure out a way to get rid of that post.

And as far as I know the o2s have never been changed. My MPG is about 19 so on the low side especially considering I do a lot of freeway.

 

Could you share with us the 'spec' the plugs were set at?

 

its called a security but the sell them at local auto stores. its a t20. O2s are probably on their way out, yeah should you getting around 22-23 with mixed driving i get about 27-30 on the free way

 

I just used what's in the Haynes book. .028 in

Do you think if the o2s were going bad it could give me the misfire issue? Maybe it's dumping too much fuel and that is what is giving the misfire.