atb

My car has started to miss at around 3500 rpms, and continues up to redline. It happens maybe 50% of the time, and if I hold it at 3500 rpms I can detect that its still there, just not as strong. I'm thinking that I've either got a plug wire or coil wire that's starting to go, just wondering if anyone else has any ideas. I'm letting my 16 year old nephew take my car on a drivers skills day on the 11th (I'll be co-pilot), and I'm going to be out of town this weekend, so not a lot of troublle shooting time.

Any input is appreciated.

daveo90s4

Adam, do the easy things 1st. For example:
1. Run the engine at night, no lights nearby, with hood up. Do you see any tell-tale blue flashes?
2. Make sure all spark plug leads and coil leads are firmly in place, coils firmly mounted, earthed
3. Pay particular attention to the LH coil wire - for some reason these are a known weak item
4. Run the engine at 3,500 revs with it missing, then immediately shut it off and check the plugs. Does one look a different colour? Likely the culprit. If not a lot of diagnosis time, then maybe simply replace all the plugs while you are at it.

I'm sure others will have better / alternative suggestions

Mrmerlin

While your doing the in the dark looking for the errant spark test get a spray mister bottle with water and lightly spray all of the wires down this will help to find the bad wire or connection, while its running

atb

merlin,
what is the effect I should be looking (or listening) for when I spray the wires?

Thanks of the input guys, its starting to get dark right now.

Lizard928

Adam, the particals in the water will create an easier path for the electricity to jump, so look for arcs

Tom. M

Check your injector connectors too...mine was doing that last TA...only upper revs would it miss...one of the wires on my #4 injector connector is loose and needs to be replaced...but reseating it cured my miss...

Good luck..

later,
Tom
89GT

mark kibort

check out the coil terminals. i was arcing from the terminal to the coil wire insulated boot.
i found it because i could actually hear it.

mk

Mrmerlin

you will be looking for a blue spark that will be jumping from one point on the wire to ground it will also make a snapping noise, kind of like the injectors,........... as previously stated after the water test check the injector wires thats a great suggestion

sharkmeister85

What kind of shape are the caps and rotors in? Plugs?
Glenn