450HP

For the last two weeks, my car has a "stumble" that feels like either fuel cutting out
or the tranny slipping...

They're several short hesitations or stumbles.

The engine and tranny have only 15K miles on them after rebuilds.

The problem only occurs on my return trip home from work... it'll do it once right after I leave work
and then just before I get home.

It's never done it on the way to work...

A friend of mine here at work mentioned that he had an Escort that had a similar problem. He tried
a test pipe in place of the CAT and he stated that fixed the problem.

He claimed that the car would stumble at the same places on the way home, but never on the way to work.

This is what my car is doing...

One more symptom is that the problem happens when I've let off of the gas pedal and I go to step back
down on it.

It will do a few "stumbles" or "hesitations", kind of like a jerky cut-out then it will be fine again.

Anyone have any ideas?

Thanks!
Scott

fold_em83

Right after I got it, my T-Bird was doing something similar. I was certain the transmission was slipping. The difference was my car did it all the time. Anyway, I would try checking some of the ignition components. I ended up changing plugs and wires on my car and it solved the problem. Don't know if this would help you at all or not but just thought I might suggest it.

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94 Thunderbird LX

bertha66

When was the last time the fuel filter was changed?

450HP

The plug wires, cap, rotor, fuel filter, plugs, & coil were all replaced within the last year.

I was doing some checks last night... even stopped by a local Autozone to have the codes
checked... only codes present were - Bank 1, Bank 2 lean.

I talked with one of my neighbors who's a mechanic, and he told me to check for possible
unmetered air intake... since a lean condition means more air than fuel... I looked over all the
intake parts and even sprayed some carb cleaner around the intake parts of the engine looking
for a vacuum leak... none found.

I stopped by a local tranny shop and explained the symptoms and we went for a test drive.

He felt exactly what I was feeling and we got to talking about the car's history and he
came to the conclusion that the CATs are plugged (they do have 160K miles on them).

I went back to my neighbor and talked to him about it and he says that it's possible... so
he's having me bring the car in to check for back pressure.

Also, while checking things over, I found that the connector for the electronic control
of the clutch packs had a little bit of seepage in it which I cleaned out very well and put
some dielectric grease in the connector.

So that's where it stands as of now... I'll know more after the CATs get checked for back pressure.

Scott

fold_em83

There's lots of things that can cause a lean condition. O2 sensors, injectors, etc. Hopefully you've got it figured out.

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94 Thunderbird LX

450HP

Well... finally had the cats checked and they were given a clean bill of health...

While driving the car today, the tranny came disengaged... I let off the throttle
hoping it would reengage... after a while it did and was fine the rest of the way home.

Is there a control box just for the tranny or is it in the main ECM?

Are there any external parts that may cause something like this?

The engine was replaced with a remanufactured engine and the tranny was rebuilt about
four years ago... so there's no warranty left on the engine/tranny.

Looks like it might be time to find a different car...

Scott

fold_em83

A tranny fluid filter and change couldn't hurt. I had my tranny in my T-Bird disengage a few times so I changed the fluid and filter. I used Valvoline high mileage fluid and haven't had a problem with it since. I've heard that Lucas makes pretty good stuff too. Could always try adding some of that first if you're not crazy about a fluid and filter change.

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94 Thunderbird LX

450HP

I'm taking the car in to my local Cottman's Transmission...

They have a free 21 point inspection... have all kinds of machines
to test the tranny (some even while driving).

So will know more after the first part of this week.

It was mentioned to me that with the Bank 1/2 running lean, to look for
a vacuum leak. I found one that I traced to a bad section of vacuum line.

The car runs much smoother than it had for a while, but the sutter is still there.

I don't think that I had the battery disconnected long enough to clear the codes
as the presets held in the radio.

Will know more after this week!

Thanks!
Scott