My son's 88Fbird 2.8L was missing during all modes of operation (cold idle, hot idle, acceleration, deceleration, cruise, etc.).
I started looking for the obvious bad cap, rotor, plug wires and such. The most frustrating part is that the problem was not detectable through using an analyzer or any other suggested testing. I went to pull the cap off of the distributor and it felt loose. So I gave the retaining screws an extra turn and it was tight again, or so I thought. Drove it a few days and the missing was gone. Then it would start again. At this point I'm thinking "should've bought the boy a Pony (Mustang).

Went to tighten the cap retaining screws again and they were really tight. But the cap was still loose. Hmmmmm.

Pulled the distributor and guess what I found. Apparently when GM built these distributors, their assembly process involved "pressing" the plate (where the ignition module mounts) onto the shaft housing. Must be like a .0001"-.0005" tight fit when new. To further secure the plate to the shaft housing, GM "dimpled" the plate in two places 180 degrees out. But with age and maintenance, the plate had worked loose from the shaft causing the distributor cap to "float" or "wobble". The cap could not come off during operation as long as the retaining screws were installed, but the ignition system sure did NOT like a movable distributor cap. I'm sure that's why there was no consistency in trying to duplicate the miss or isolate a specific condition when it would miss.

Now for the good news. I had two choices, spend $115 for a remanufactured distributor or have a welder "tack" weld the plate back onto the shaft housing. As an airline mechanic, I have several co-workers who are welders. The trick was trying to match a good weld wire with the parent metal of the housing and plate. The best guess was AMS 6061-T0, cast aluminum. I will caution you to remember two things:

1. Remove ALL of the electrical components from the distributor. This includes both the ignition module and the pick-up coil.

2. Remember, aluminum is tricky stuff, so I suggest you only allow someone experienced in welding aluminum to attempt this.

You'll have to clean the welded surfaces by brushing them to remove surface corrosion (common to cast aluminum). Also, let the pieces cool down slowly. DO NOT RINSE IN COLD WATER TO SPEED UP THE COOLING RATE. This could cause the aluminum to work harden and/or change the temper in the metal resulting in extreme brittleness or softness.

I re-assembled, installed and performed the timing check per the manual. She's no V8, but she runs like a striped-***-ape for a six!

Hope this helps someone....

Later dudes and dude-ettes!

 

interesting. I'll have to start checking mine now and then or remember that if I start having problems. thanks for the info

 

Thanks for the info on that, it is one of those obscure things that can take forever to nail down even when you are looking at the right part(*** knows it has happened to me before, lol) plus my distributor likes to give me problems now and again so that is an extra thing to check next time before it gives me a problem, thanks again.

 

I agree, thanks, A88!! So many people ask about how to fix a problem, we tell them info, and they never tell us how (or if!!) they fixed it.

Your message is the complete opposite of that! Thanks for the tip; I think tomorrow I'll out and see if my distributor cap wobbles around!

 

Coolrims, Vamp and TomP,

It's been several days now. This is the longest this FBird has idled correctly since purchased. I can't believe how stupid I was in overlooking the obvious. We got snow over the last two days (lots of it for Tulsa, OK) and my son gained a healthy respect for speed and braking distances on snow and ice. We even had fun cutting donuts in empty parking lots.

Thanks again for the advice and info found on this board.

 

Well, its February which means cold weather here in Okie land (or bubba-ville depending on your perspective).

This little V6 Fbird is still idling smoother than a babys' butt.

It appears to me that the loose distributor plate was the real problem all along.

Sending this back to the top hoping someone else can use the advice.

They should give out awards on the net for "Most Informative Web Site". It would obviously go to "Thirdgen.org, V6 Board"!