2003 Malibu V6, 3.1 no power, no acceleration

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  #1  
Old 07-06-10, 08:44 AM
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2003 Malibu V6, 3.1 no power, no acceleration

I have a Malibu question (2003 Malibu, 3.1, auto, V6).

The car seems to be "holding back", "dragging", not getting any power, no acceleration.

You have to give it a lot of gas for it to go, especially up a hill or at acceleration. Even accelerating up a small hill you have to practically floor it.

With the car in neutral the engine runs fine. The car does not pull one way or another and rolls fine when in neutral (so its not the brakes dragging). There is no check engine light on (but I will scan for codes today just to make sure) and there are no weird noises or smells and I have noticed no leaks.

This has been progressively getting worse - since I don't drive it usually (it's my wife's car) I wasn't at first sure if this wasn't just the way the car drove but now it is so noticeable we don't even drive the car.

I have a old Toyota that shifts right from 1st to 3rd and for those speeds when it should be in 2nd, the Toyota kind of drives similarly to how the Malibu does now - no acceleration and no power, but for the Malibu it does it at all speeds while in the Toyota it only does it when it should be in 2nd. I feel no harsh shifts from the tranny - although I can't now recall feeling the tranny shift at all - but I wasn't paying attention either. Could it be the tranny? Is there a "limp home" mode in the tranny like they used to have in the old car engine computers?

Any ideas or suggestions?

Thanks
 
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  #2  
Old 07-06-10, 09:27 AM
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If regular maintenance has not been done on this vehicle, I would do everything the manufacturer recommends. Like replace fuel, oil, air filters. Change oil. Replace and clean other parts as recommended... Everything recommended by the factory service manual set of books for the mileage it has. (Order factory service manual sets from dealer of helminc.com)

Then if still having the problem, I would start by checking the fuel pressure and flow volume. More on that here...
Fuel Injection Service, Not Just Cleaning
 
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Old 07-06-10, 10:04 AM
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Two years ago I replaced the fuel pump and fuel filter and last year I replaced the intake manifold gasket/belts/plugs/plug wires/pvc/air filter. The car has about 100k miles on it.

If it was the fuel pressure/regulator/flow... wouldn't this create an error code?

Thanks
 
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Old 07-07-10, 06:00 AM
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Update - I scanned for codes and there were no codes set. Also I took it on an extended test drive and if I drove it very moderately - a slow poke and only gradually increasing speed on a flat road it drove fine, but the minute I tried to accelerate fast - like on the on-ramp to the highway or going up any hill I had to give it a lot of gas just to keep the speed up. From stopped driving up a very small hill the car hesitated horribly and I again had to give at a lot of gas. I noticed no abnormal tranny shifts.
 
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Old 07-07-10, 07:11 AM
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Originally Posted by shinrich View Post
If it was the fuel pressure/regulator/flow... wouldn't this create an error code?
Might show too lean if the oxygen sensors are working like they should. That is another regular maintenance item. I've read these should be replaced every 30,000 miles. Elsewhere I've read these should be replaced every 60,000 miles.
 
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Old 07-07-10, 08:05 AM
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If it were my car my laundry list would be:
Check the gap on the plugs.
Check fuel pressure.
Verify parking brake is not partially engaged. Remember that's just what I would do if it were my car.
Clean MAF sensor using MAF sensor cleaner.

But if you give it gas and you get high revving and lack of power then take a look at your trans fluid level.
 
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Old 07-07-10, 09:38 AM
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Do you think that a possibility could exist that the fuel filter needs changing again even though it has only been 2 years? If not too expensive I know I would be tempted to throw on a new one. Do you also know if the correct GM recommended long life plugs were installed when they were changed? Some of the cheap ones won't last very long. It might be worth pulling them and checking them as has already been suggested just to eliminate more of the simple things. Also would a bad Catalytic Converter be a possibility.
 
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Old 07-07-10, 10:00 AM
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Since a couple of mentions were made about the cat converter, how would I tell if mine was bad? I mean it is way to expensive to replace just on a hope. Thanks
 
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Old 07-14-10, 06:36 PM
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Clogged catalytic converter.... to test it, you have to disconnect it from the engine, and then the car will FLY and you will surely know you need a new converter
GOOD LUCK!
 
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Old 07-14-10, 09:28 PM
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One way to DIY test the catylitic converter is to drill a 1/4 inch hole in the exhaust pipe ahead of the converter. Inserting a 10 pound pressure guage using a 1/4 inch pipe attached to the hose will let you read the pressure prior to the converter with the engine running. Pressures of over 4 pounds likely mean that back pressure is building that will affect engine performance. Insert a 1/4 inch metal plug into the exhaust pipe afterwards to seal the hole after testing it.
 
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Old 07-15-10, 07:17 PM
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What I meant to say is, YOU HAVE A CLOGGED CATALYTIC CONVERTER.

I know the symptoms and I'll stake my reputation on it.... LOL!!!
 
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Old 07-15-10, 07:50 PM
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Rebels Got it......

BUT........Before you drill, or go flying down the highway with pipes hanging,.......Just simply remove the o2 sensors from the pipe ahead of the converter( Engine side), and drive the car.......The "Holes" leave a place for the exhaust to escape, Basically bypassing your exhaust stystem.

If by chance your cat has Fractured internally, It is not uncommon for the debris to choke a muffler, so be prepared.
 
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Old 07-16-10, 05:35 AM
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I think I will try the cat - but one question about removing the O2 sensor to test the cat - if I do this, won't it give O2 error reading to the computer and then the car will run lousy. How will I know if the cat is the problem if the car is running lousy from no O2 sensor? Thanks
 
  #14  
Old 07-16-10, 09:26 AM
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I think at first vehicles run in "open loop" mode and don't use the oxygen sensor information. Then after vehicle is warmed up, it goes into what is called "closed loop" and uses the oxygen sensor info.

I would think if it is running bad from the get go, then you remove the oxygen sensor and it runs good when cold, then that would be a valid test.

Also be sure to apply "anti sieze" goop to the oxygen sensor threads before reinstalling. This makes it easier to remove later on. Or should I say makes it possible to remove!
 
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Old 07-16-10, 03:18 PM
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First off, Please understand that removing the O2 sensors is only a TEST procedure, It isnt a fix. Prolonged usage with a hole in the exhaust is a Fire hazard. Only drive the car enough to be convinced that your problem lies in a restricted exhaust.

Most O2 's in a closed loop feed back system are designed to affect "Long Term Trim" ...Which basically means that they have Very little to no Immediate effect on performance or Driveability for the short term, so As far as affecting performane to the point of not being able to tell the difference.....Never gonna happen....

Second.You are only looking for a change in performance, (Either good or bad). It isnt going to restore the new car feel, But if the catalyst is plugged, you WILL feel a drastic difference the first time you throttle the car.
Without trying to "DATE" myself..Ive been doing this test for over 25 years, and I have yet to find a Bad cat that I couldnt Identify by this method..
 
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Old 07-27-10, 05:45 AM
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Everyone was right - it was finally under 100 degrees here so I was able to take the O2 sensor out and the car did drive 100% better. I've never had this happen before and I would NEVER have thought about it if you guys had not suggested it - thanks!
Now for more questions - Should I replace the cat with an exact fit replacement or a "universal" that I cut and clamp onto the remaining pipe? First - do they even sell such replacement cut and clamp cats? I'd prefer to spend the extra money and do an exact replacement, but the pipe at the front end is held on by two bolts/studs and my experience is that these GM exhaust studs break and then I'd be scr*wed. Do these two bolts/studs that hold the cat pipe to the manifold tend to break? Are they even the studs I'm thinking about like the old Chevy's or are they just bolts that if they break will just come out and can be replaced? Finally, since I took the upstream O2 sensor out, should I just go and replace it while I'm at it - I'm at 7 years and 110k?
Thanks Again!
 
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