Miss fire - HELP!!

chopper666 · 4-4-06, 2:41

Hi all,

92 manual 122k

started to miss fire while i was in scotland, driving fine then just started running rough.
garage there found oil in the first spark plug only, cleared it, new spark plugs and patched me up so i could drive home, suggesting a front rocker gasket replacement, distributor cap & rotor arm. cruise did not work on way home, when it had operated fine prior to miss fire / patch up
Had these all done yesterday at local garage, distributor / gasket / rotor arm. (first spark plug appeared oil free) car now still continues to miss fire. cruise still does not work. it is very rough at idle and pulls very poorly when accelerating.
Please help - i am no mechanic, however can access a good mechanic now (not same as went to yesterday) so any ideas what direction to go would be helpful.
what sort of costs will i be looking at ? is it fatal?
Many Thanks
Rich

**Russellg** · 4-4-06, 6:06

Have you checked the plug leads?
These degrade to a point where performance is affected at about 80K. If they haven't been changed then that could be the issue. The other main ones that a non techie like me would suggest you have covered.

As for the cruise control.. no idea, but suspect a disconnected lead when the 1st garage was fiddling.

Experts????

Russ

**Stoatman** · 4-4-06, 7:03

Very similar problem to this. Changed plug leads and all is well, my suggestion. Def change them. Not too expensive to do so.

**Einstein** · 4-4-06, 10:28

What type of plugs are fitted now?

maybe they are the wrong type..

Agree with leads...

Cruise is pretty simple, and gets reading from speedo.. there is a small control box under the dash... other things connected are brake switch, clutch switch and neutral switch...

Check the "meter" and "stop" fuses.

John

chopper666 · 4-4-06, 11:40

sorry dont know what sort of plugs are in it now .
come to think of it the bloke that did the rocker gasket & distributor cap etc did comment that the ignition leads looked like they could do with replacing.

car has full mazda history up to 90k approx, any idea at what mileage this would have been done as part of dealer service?

also the first bloke to look at it (when i was in scotland) put a timing gun (?? no too technically minded??)
on the ignition leads and some were fine & some were off.
could this all be down to the ignition leads?
thanks all for your input up to now

**Oddball** · 4-4-06, 14:18

mmmm .. running rough and cruise not working, share a possible reason .. vacuum pipe.. might be worth checking the vacuum pipe from the top of the cruise control bolted to the drivers side wing just next to the air intake elbow, this pipe should run to a nipple on the no.6 inlet manifold branch just to left and rear of the distributor.. there should also be another shorter pipe coming off that branch also that goes to the FPR solenoid attached to the air intake box.

Oddy.

**Boadicea** · 4-5-06, 3:51

Pull your engine codes and see if you have any errors before you do anything else! I had the same symptoms and it turned out to be a sensor in the distributor. I had a code 3 and all I had to do to fix it was realign a plate inside the distributor. It's possible that when they changed the front gasket, they didn't fit it correctly.

Check my thread for more info:
http://www.mx6.com/forums/showthread.php?t=142558 (Rough Idle (jerks/splutters/coughs))

chopper666 · 4-5-06, 4:25

would this work on a 92? does it have the engine computer?

**Storm** · 4-5-06, 4:37

Quote:

Originally Posted by Oddball

the vacuum pipe from the top of the cruise control bolted to the drivers side wing just next to the air intake elbow, this pipe should run to a nipple on the no.6 inlet manifold branch just to left and rear of the distributor.. there should also be another shorter pipe coming off that branch also that goes to the FPR solenoid attached to the air intake box.

Oddy.

Exactly the same one I was talking about on my thread - there's an "inverted" T pipe the horizontal pipe was connected but the vertical pipe was open to the atmosphere - blocked it off (induction kit fitted) and renewed the ignition leads, and hey presto - smooth running and more grunt low down in the rev range. Also cured my occasional but very severe misfire.

If that's of any use.......

G

**Boadicea** · 4-5-06, 4:52

Quote:

Originally Posted by chopper666

would this work on a 92? does it have the engine computer?

Yes, it should work on a 92 model. If it's a UK car you will need a paperclip and an LED. There's more info on how to do it here:
http://homepage.ntlworld.com/mx6-uk/malf/malfcode.htm
Let me know if you have any questions.

If I had done this right at the start of my problem I would have saved about £300 on "possible" fixes....