Babynrse

Hello all, I have a 2002 Chevy Venture with 158,000+ miles. I started having issues with the car running rough, at times it felt as if it would stall, and other times it felt like it wanted to take off with pressing the accelerator. I also noted that if I tried to accelerate at times the check engine light would flash. I had a similar problem last year and in Sept 2013 the EGR valve, fuel injection pressure sensor, and fuel filter were replaced. It was running fine until now. I took it to my local auto parts store and had the codes read, they came up as P0128, P0300, P0401, P0404, P0405, and P0406. I have not driven the care in a week, and went out this afternoon and started her up and she ran without a problem. Now I did not leave my driveway, just idled and reved the engine a few times and nothing happened. I need to know what I can do to further troubleshoot the problem. I can not take it to a shop, as I can't afford it. Thank you ahead of time.

sergeimoskva

Hi!
Code p0128 - is not only thermostat. Possible failure of the sensor temperature.
Code P0300 - is likely caused by faulty spark plugs, wires or lack fuel problem.
Try to change the spark plugs

Babynrse

The spark plugs were just changed this past sept.

in2pro

Babynrse Welcome to the forum...
Its only a guess but its possible the catalytic converter has become blocked leading to the poor performance... your not likely to see it sitting in the drive way because the cat is able to handle that amount of exhaust but when driving that is a different story....
I would suggest a reputable shop read the O2 sensor values...if its a cat the O2 sensor readings will show it.....

sergeimoskva

Hi!
in2pro
If the oxygen sensor or catalytic converter, the computer will emit code P0133.P0135 or P0420.P0430. But these codes do not.
Babynrse
If generalize common causes of fault codes (P0128, P0300, P0401, P0404, P0405, P0406), then maybe it is caused by vacuum leaks (cracked vacuum hoses, leaky intake manifold gaskets , dirty fuel injectors or low fuel pressure )
Undoubtedly - you need all that I told you - check

in2pro

sergeimoskva I agree, those are good points, but given the miles on the vehicle and that its maintenance could be in question ( having drive-ablity issues for period of time) I still wouldn't rule out the catalyst as a problem...
I do agree those are easy and free things to check i.e. vacuum leaks, cracked hoses...

Babynrse

Thanks for the info, if it is the cat converter, what if any would be the symptoms? Also I have had this car for 8 years and take very good care of it. The mechanics that I have had to take it too when there is something that I cannot fix, they have always commented on the condition of my vehicle. I inspected the hoses and they all appear in good shape. I also don't hear a high pitch hiss. I did find the elbow connector to my PCV valve was cracked in two places, so I have replaced that.
I do have another question though, I started her up after replacing the PCV elbow and she was running fine, I let it run for a good 20-25 minutes just idling and my temp gauge only went up slightly. It was 98 degrees out and the fans did not kick in. I read that the P0128 could be from an faulty coolant temp sensor. Do you think that may be the case?

Babynrse

I am going to check the spark plugs first, but I'm afraid I can only get to three of them at this time. I have to borrow a jack and stands form my dad in order to get tho the other three. i will let you know what I find. Thanks

Janey

Hello, not to but in, but if the EGR needed replaced already, the entire emissions control system is in question. The tube going to the EGR might not have been cleaned out good, causing the new part to get gunked up after the replacement. Could be that it just needs a good cleaning in lots of places from all the bad crud in the fuel these days getting stopped up inside small tubes and bends in connections.

Most of the things are fairly logical to clean up, just spray some B-12 Chemtool or other cleaner down the tube and shake it dry (after unhooking both ends of course), but be very careful with the MAF sensor! The Mass Air Flow sensor is inside of the large air tube going away from the air filter box toward the engine, and it has to be sprayed clean with a special cleaner or it will cost a bunch to replace it. The last can of the cleaner I bought only cost about $6 at Autozone, and it saved me a $95 replacement part.
Replace any of the vaccume lines you find crunchy, and it might just finish off what could have been very expensive labor-wise for mechanics hours.
Lots of luck to you! Its a nasty job...

Janey

Oh, btw, just noticed you were asking for symptoms for the Cat Converters going bad. I helped run a muffler shop and garage for over 20 years, and kinda know a thing or two about those too.

First, you should smell rotten eggs... thats the sign the guts of the converter are getting worn out. (Chemical reaction, scent of Sulfuric Acid too strongly.)

Second symptom... loss of power on acceleration or going up hills, (they stop up and the air can't be moved out of the tail pipe properly).

A good simple test for bad converters is to have someone rev the engine while you put the palm of your hand over the tail pipe to see if the air pressure increases right. If you don't feel much pressure, it could be broken up inside and the guts stuck in the exhaust pipe, or melted down inside from something as simple as getting a bad tank of gas (reacting with the honeycomb type configuration of the materials the insides are made of and squeezing them shut).

Remember seeing cartoons or idiot kids on old tv shows shoving a potato or a banana up someone's tailpipe to disable their vehicle? Thats what Converters do when they go bad... its just not funny being stuck out on the highway when it happens.

The extreme heat and pressure a converter backs up onto the engine can cause a world of problems too, so if it isn't putting out sufficient airflow, it will ruin the spark plugs first, (melt down sometimes) and all kinds of important emission control sensors, and if bad enough stopping up suddenly takes place on the freeway from a broken up converter, it can blow out the gaskets on the engine itself.

The computer test for the actual converter being stopped up only checks the pressure coming out of the tail pipe... there are no codes for a broken up or stopped up converter unless you guess that it is what burned up a sensor when you get those sensor codes showing.

Good luck! And Happy 4th of July!