All of a sudden I have a miss

[GH85Carrera]

My 85 Carrera has been running fine except sometimes when it is stone cold the first 60 seconds or so it will have a little hesitation.

I recently put in a can of BG44 and that seems to have helped. I finished that tank of gas, and did an oil change & fuel filter change. I filled the tank with fresh ethanol free gas. I have used about 1/2 of that tank.

On Saturday I went for a drive to check out the AC. It was 110 freaking degrees here so it was the ultimate test for AC. I am happy to report I had 40 degree vent temps with the blower on max. The engine temp was a 215 degrees as I was coming back home. The engine started to idle rough sitting at a light less than a mile from my house. It was suddenly running on 5 cylinders. It seemed to smooth out as I pulled in the driveway and parked in the garage. It was 110 outside and my engine was at 210 so I figured it was a good time to worry about it later.

This morning I thought I would drive it to work and see how it does. It is running on five cylinders for sure. I drove it about a 1/2 mile and turned around and went back home and drove my regular daily driver to work.

So my real question is who is the best guesser on the board. I don't think it is the plugs or wires as the plugs are about a year old and the wires are two. I am guessing I have a piece of crud in one injector. I am hoping it will clear itself out if I drive it a mile or so. What is you guess. I will have to find a CURE for this ASAP since I will be driving to Savannah GA in just a little over two weeks.

[MotoSook]

Obviously you want to check the simple stuff first. Despite the new plug wires its easy to check resistance, positive engagement of connectors and the plug itself.

If you have spark at all six (I use my timig light and move it from wire to wire) and you are not firing on all 6, check with a spray bottle and spray the exhaust when starting from cold to identify the dead cylinder. Pull plug and see if you have fuel going in. If no fuel, try an old injector if you have one or borrow one or swap injectors and see if it follows. Might as well clean the injectors best you can while out.

[MotoSook]

Is it a constant miss? Are you sure it's a single dead cylinder? When was the fuel filter changed? Do you have a spare fuel filter to check?

Over the last month I've tagged two 911s with bad fuel filters.

Start simple.

[GH85Carrera]

The filter is brand new. I was planning on checking each spark plug at the engine. It is strange that is was running just fine and just bam, something changed. That is why I am guessing it is a injector. I will definitely check the electrical part first just because it is easier.

[GH85Carrera]

Originally Posted by Soukus

Obviously you want to check the simple stuff first. Despite the new plug wires its easy to check resistance, positive engagement of connectors and the plug itself.

If you have spark at all six (I use my timig light and move it from wire to wire) and you are not firing on all 6, check with a spray bottle and spray the exhaust when starting from cold to identify the dead cylinder. Pull plug and see if you have fuel going in. If no fuel, try an old injector if you have one or borrow one or swap injectors and see if it follows. Might as well clean the injectors best you can while out.

That is a good idea about spraying with water, thanks.

[MotoSook]

A buddy installed a new filter on his car. A few days later he goes to the track. Problems at the trackade for a poor weekend. Problem: fuel filter. A full tank or a fill up caused enough debris and crux to come loose and choke the filter.


It's easy enough to remove the filter and check it. My buddy claimed the brand new filter was dripping with goo.


Good luck.

Eta: he had just cleaned out his tank and replaced the tank (CIS) strainer. I helped him pull the strainer. So don't assume anything...at least not the simple things. Your recent fill up with ethanol free gas may have knocked enough crud off the walls or the tank to cause a problem.

[rnln]

even if you said so, I will ask anyway. What kind of pugs you are using? When I was having platinum, I had missed very once in a while, maybe once a year when it's cold, at high speed freeway. Replace all those "tune up" stuff but eventually it happend again, very rare. After switching to the famous copper plugs, it's gone, several years now.

[MotoSook]

Platinum plugs are the worst things ever invented for old cars....

[GH85Carrera]

I always run pure gas when I am in Oklahoma. The only time I buy the other stuff is on road trips to other states.

The old filter looked pretty clean after three years of duty.

[GH85Carrera]

Just to follow up for all those that were on the edge of their seats waiting for the answer.



It was this plug wire connection at the distributor. You can see the green evidence of corrosion on the wire & the connector. It just pulled right apart with a slight touch.

Now I have to decide if I can just clean it up and make a good tight connection or should I buy new wires?

[DRACO A5OG]

Hewh! I thought it was the BG 44K You scared the crapo out of me.

Whoa, just replace brother why take a chance of a bad contact or worse errand sparks

jim

[rusnak]

My vote would be for new wires.

[MotoSook]

Simple pays off again...