:banghead::banghead::banghead:I have this problem that I cannot figure out and it is killing me!! My 93 deville is my baby but it has this problem that I dont know if it can be fixed. Often when I am driving for no reason and it does not matter how long I have been driving it gets this horrible stutter. I will give it gas and it will not go (well fast at least). I have to go a very slow speed like 10mph. And that does not work on the highway.
When I push the gas I get a very weak and delayed response and I have to resort to a coast (not fun with your family on board). I have tried many things and asked mechanical advise but nothing. so please board I am turning to you because I dont want to lose my baby. But I cannot afford to DIE on the highway when if the continues to occur. Here is what I have done so far.
Tune up with AC delco parts
Fuel filter and Fuel system cleaned
Transmission fluid added
New K and N like filter

I am a novice and I dont have the funds to continue to guessing. I should mentioned that this has been going on for some time now but I went away for appx 7 months and decided to return this week. Well I that you in advance for your support.:banghead::banghead:

Since it is an intermittent problem, perhaps an ignition system problem?

Be sure that all the connections on the ignition components, especially plugs/wires are secure.

Make sure all grounds are secure and free from corrosion.

Maybe the ignition module has failed?

The first thing you should do is to get rid of that k&n filter and put in a good paper filter.

Have you checked the codes? That should give a hint. Other things I though of is the egr valve, o2 sensors, fuel injectors...

Also, you say that you did a tune up. Does that mean that you only did spark plugs and wires? You should check to see that you are getting a good spark.

An intertittent problem like that can be extremely hard to diagnose. A weak fuel pump is another posibility. As suggested, start by pulling the codes. That may give you/us a clue.

Remember one point -- the computer never tells on itself !!

I went through this exact same thing with a '93 Deville, and after trying replacing the ECM, and a dozen other parts decided to just trade it to the local Mercedes Benz dealer. He said thet after working on it for days it involved replacing the BCM and ECM. I don't believe it. It was baffling and dangerous. The car had supposedly not been in a flood, but was in an accident in Florida. It was a curb sale through the Cadillac dealer, but I think they lied. The car worked perfectly and after a year crapped out. I tried everything. Finally I took a $3,000. hit on it, and replaced it with a 1996 Lexus.

Traded in my 1991 STS with 86,000 miles in, which I had had for four and one-half years, and the subsequent purchaser reported the same symptoms.

Only commonality -- both cars were dark green metallic ??

Turn ignition ON and press Warmer and OFF simultaneously until codes show up on the driver info. center.Write them down and compare with this: http://www.cadillacforums.com/forums/ht4100-4-1-4-5-4/21558-obd-i-codes-4-x-engines.html )

If you get bunch of codes it may be as simple as a bad ground. Fuel pump is another suspect as Ranger mentioned. You will need a fuel pressure gauge taped to your windshield to see the reading when it happens again. First pull the codes, and report here.

This one can be tough but can be overcome. Well equipped shops will have access to technical service bullitens which might just outline the exact problem. There are diagnostic tools such as snap-on's MODIS which can be set to monitor several sensors at one time and record the sensor's output. When it glitches the evidence will show up. Pulling codes might just lead you in the wrong direction unless the information is used correctly. Could be an ECM but that is only an expensive guess. Could also be ignition. A highpot failure in a coil can come and go with temperature and required firing voltage variation. Good luck.

I will pull the codes and try to figure this out. Again I hope I dont have to get rid of my car.

Pulled my codes and all I got was .7.0 nothing else. I would like to emphasize that this problem just recently began to happen again. We would it stop for a few months and all of a sudden reappear. I truly thank you for your help but this is killing me. When I go on a drive I never know what to expect and that is a very uncomfortable feeling.

Can someone please help me with these codes.
. .E
E39
E.0.0
E.9.0
8.8.8
F.8.0
1.3
1.7
Again I apologize I am a novice and really dont know much about this stuff. I really thank everyone who views or replys to my posts.
It is just hard to get around town when you know that your car will begin to act out at any given moment.

Hello -
I was just passing by and accidentally happened to drop in as I was looking for another board. Your problem, however, really struck a nerve, because it was EXACTLY the problem which baffled me and the dealership which supplied the company FORD I was driving many years ago.
It was a brand new (well, actually 6 months old, with 9,000 miles) car.
I was driving along on I-65, north of Indianapolis at about 70 miles per when the car just slowed down.
I pushed harder on the pedal but the car simply wouldn't "obey" until it got down to a walking speed and I was on the shoulder and I let off the gas.
Then it ran fine at idle.
I put the car in neutral and goosed it and it revved up just fine, roaring nice and loud.
I put it in gear and, when it was clear, I got back on the highway and floored it.
The car went up to about 50 and the same thing happened - back to a walking speed and I pulled to the shoulder again.
I crept along to the nearest exit and followed local streets no faster than 30mph to the selling dealer.
I called my office to cancel my out-of-town appointments while I had to cool my heels as the dealer went nuts trying to find the problem.
Bottom line:
WEIRD: Baffles in the muffler had broken loose and at high speed under load had slammed shut against the outflow opening!There was a spring-like action.
When I backed off, there was less pressure and the motor ran fine, but when I pushed it, the baffles shut the door, so to speak.
Talk about WEIRD!
I have no idea if you have such a completely out-in-left-field problem as this, but that's what happened to me.
Then again, what happened was to a FORD!:thepan:

E.39 = VCC engagement problem. This is the classic VCC problem that pretty much all Devilles of this vintage will have. The fact you see a single "E", means this history, not current. This isn't causing your current problems, though.

"E.0.0" means you may hvae cleared the codes first? Why did you do that? (you pressed "Off" & "Hi" after entering diagnostics). However, E.0.0 could mean other things depending on what buttons you pushed.

E.9.0 means you pressed "Lo" to look at the PCM data. This isn't useful unless you have the FSM.

F.8.0 means you presssed "outside temp" - allows you to override some computer functions. Be careful about screwing with this.

1.3 and 1.7 are not in the FSM. You sure you got these two right?

Still having the same issues. I rarely have to drive more than 50 miles at once but whn I do I get the same old stuff. I have to barely press the gas in order to get the car to move and on the highway going from 0-60 in 2minuites is not safe.

A clogged catalytic converter is always a possibility. Have it checked out at an exhaust shop and see what happens from there.

When this happens and you stick it in neutral or park and gun the engine, does the engine stutter?

Run down to your local auto parts store and get yourself a $20-$30 fuel pressure gauge, the kind with a shrader fitting. It goes on the fuel rail schrader valve, which is on the left-hand side of the engine (driver side) on the front cylinder bank. It will have a cap on it. BTW, a shrader valve is the kind of valve that tires have.

Keep the gauge in your car. When this problems happens to you, while it is still exhibiting the symptoms, screw on the fuel pressure gauge, fire up the engine. Gun the engine. Make sure the fuel pressure stays around 40 PSI at all times. Shut it down - it SHOULD STAY around 40 PSI for a loooong time.

If you see pressures lower than this (38 might be ok, though), you have a problem with your FPR or your fuel tank/pump/sock/lines.

For safety, you'll want some rags and a fire extinguisher. Attaching/removing the gauge will cause some fuel to spray out.

Sounds like you are not well equipped to diagnose and service this problem yourself. I can think of many things I would check and work on, but as you noted trial and error is not very practical. Take it to a good shop and let the pros figure it out. Just give them the most detailed and thorough description of the problem you can.

Rick186 had a good point.
Hit the muffler and cathletic convertor with a hammer or something and if they rattle they have some loose parts inside them that block off the exhaust.