Stalling and will not go faster than 9-18 MPH, stuck in limp mode?

Hi,

Are there any diagnostic trouble codes stored? If you haven't checked for codes, start with that.

Here is a quick video showing how it's done:

https://www.youtube.com/watch?v=b2IJGfImVvw

Next, if there is no power, one of the first things that comes to mind is a plugged catalytic converter. If there is a restriction in the exhaust, this can happen.

Take a look through this and let me know if you feel it mirrors what you experience:

https://www.2carpros.com/articles/bad-catalytic-converter-symptoms

Let me know.

Joe

We looked at the catalytic converters, they look fine, told though check valves, how do we do that?

If we look and can see through them, screens look clean so that tells me they are not clogged, right?

If you can see through them, they should be okay. The easiest thing to try is to remove an oxygen sensor upstream from the converter. If the converter is the issue, the O2 opening will allow an exit for the exhaust. It won't be perfect, but it will be enough to make a difference.

You asked a question in your first post. I'm not sure what you are referring to. You asked, ". Told tho check check valves, how do we do that?" What are we checking?

Let me know.

Joe

The combination valves.
How do we know that they are bad? When we are looking at them how do we test them, what tells us they are bad? Also, the test, after we clean it, we need to calibrate, right? For the car listed above, 5 and 4.5?

Hi,

I am so sorry, but the only combination valve I'm familiar with is the brake system. Take a pic of what you are looking at and upload it for me to see.

Take care,

Joe

Okay, some good news, switched out MAF for the third time in 3-5 months. Sounds much quieter! Got up to 35 MPH on test drive.
Think maybe O2's next to double check. Secondary fuel injection may have ruined all the previous stuff we have done lately because it was beat up. But after replaced MAF, check engine light finally turned on, yay! Now retry for codes. Anything pop up now? Po102 MAF low circuit. Wow something finally! So, is it wiring? What makes low circuit code? Wow thanks all of you for helping the past few days! So Odb2 working, going to bring it in tomorrow- hook it up, see what happens.

Hi,

When you have low voltage in a circuit, the most common cause is either a loose connection or corrosion at one of the connectors.

When you replaced the MAF, was the connector in good condition? Check to see if there is any corrosion on the pins or if one is pushed out or damaged.

Let me know.

Joe

I don't understand why 3, 4 times within 6, 7 months we had to exchange the MAF. Are they bad when we get them from the parts store? Well, switched it out again last night and major improvement. Nothing under the hood is corroded, it's really clean, checked all the fuses but going to do it again, can I check them one by one with the multi meter? Or does it have to be the 12-volt test light? Going to check for lost or damaged pins. Wouldn't that be obvious just looking at it or is it more complicated? I'll YouTube to see. So, besides fuses and the connector, what else causes "low circuit"? Thanks everyone!

Hi,

Yes, you can use a voltmeter rather than a test light. As far as the low voltage, that can be a faulty module, a damaged wire shorting to ground, and so on. Also, there is nothing other than inspecting the connector pins for damage. Just make sure they are not bent, pushed in, or corroded.

As far as the parts you are getting, since you had issues, try a different brand. Some of the parts we have been seeing are poorly made and faulty out of the box.

Let me know what you find.

Joe

Man, went for a quick drive last night after replacing the MAF sensor the third time in 4 months, instead of 15 MPH, got up to 35. The engine sounded smooth and quiet. Tried to test drive today, now can't go pass 5 MPH and it starts jerking, sounds bad again, bog sound came back. I feel like we have tried everything.

Been searching Google and YouTube 24/7. Been mentioning bad coil pack? Just replaced that about 6 months ago. Sounds like it's misfiring again, I think that's how this all started almost a year ago. Under warrantee so we will try this as well, I guess. This is rough I need to get back to work. Been stuck out of town all this time.

Hi,

I didn't realize you were out of town. If you are feeling a misfire, it certainly could be a coil-related issue.

Let me know if that takes care of the issue.

Joe

Well, I appreciate the help from everyone. We had to get the car towed back to town. It's strange that it seemed to get better than twice as worse the next day, each time. So, now the car won't even start. I need to find a Cadillac lover to buy from me I guess because I need a running car right now and have nowhere to park and work on this car. It's finally giving us codes saying multiple misfires, but we don't know what cylinders. This is sad cause we love this car, it's in such good shape and has been so great since we bought it 3, 4 years ago. Maybe all the air injection and MAF, o2 sensor and everything just threw off the computer or something. We are just stumped and hopeless. Thanks again!

Hi,

Is a P0300 the only code you are getting?

Let me know.

Joe

Yes, one code said multiple misfires. I'm so bummed, taking good care of this car now I don't have a clue what to do, can I even sell it? I don't want to anyway I'd so love to fix this car. Thanks for your help! Really

Hi,

I can tell how important this car is to you, so let's try our best to get it fixed. Since the only code is a P0300, it could be several different things. For example, fuel pressure, vacuum leaks, engine compression, and the list goes on.

Let's start from the beginning. Explain the exact symptoms that you are experiencing, and what has been done, and I will do my best to get it figured out for you.

Take care of yourself,

Joe

Hey, it's me Starr.

Hope I can ask you on this site, we're a couple hours away from test driving a 2003 Ford Explorer. Cadillac is not running still.
Can you tell me what to specifically look for in this model?
Appreciate your help.

Hi,

I just noticed this question. Sorry for the delay. As far as an Explorer is concerned, they are solid vehicles. However, I'm not sure where you are located. If you are where salt or chloride is used in the winter on the roads, check for rust issues. The floor, inner rocker panels, around the fuel tank filler, and check bumper mounts.

If it has a 4.0L, they are a good engine but make sure it has been maintained. I'm not sure how many miles are on it, so do things like removing the oil fill cap and look down inside to make sure it isn't caked with dirt. If you have a scan tool, take it with you to confirm there are no codes and that nothing has been recently cleared.

With the hood open, inspect it for any oil leaks, evidence of wiring repairs, and vacuum hoses that are disconnected or damaged.

Let me know if that helps or if you have other questions.

Take care,

Joe

You guys have been so great to me. Well, I was reading about the specific year I was about to buy and said that the transmission ends up having catastrophic failure because of the timing chain cassettes, made of plastic and ends up breaking up and getting everywhere. Then reading about possible rough idle and stalling, which I just delt with on my 2003 Cadillac, and the way the guy answered my questions with "we'll all cars have problems", then some. I'm happy so far, I ended up getting a 2004 Suburban priced at $3,000 for $1,700.
I'm so glad I found your site, I enjoy reading all the posts from everyone about their cars, great way to learn. Lots of happiness to you all- Starr.