Hi I am hoping someone can help me! Sorry in advance for this being so long.

I have a 2006 Uplander. It's a 3.5 Engine and 2 WD I believe. We are just shy of 145,000 Miles on the car and the second owner. Our Check engine light has been on forever and the code that we were pulling was P0449. We thought it could be a bad gas cap so we changed it. It didn't help. The car was running fine though so we just let it go. Well in the past 4 months or so we started running through gas like water. My husband works about 50 min from home and we were using about a quarter and half to a half of a tank every day. We figured we would do a tune up and we hoped that would help...well recently..I would say in the past two weeks we started noticing a hesitation when we would try to accelerate. If we let our feet off of the gas it will shift but it doesn't shift how it should. We changed the plugs and wires and the air filter. My husband pulled the codes on the car and we pulled a whole bunch. One of which was for the mass air flow sensor. He cleaned it and all of those codes disappeared but left the P0449. Our first thought was transmission. We took it in to a trans shop and he hooked it up to the scanner and took it for a drive and he said no codes were being pulled. He said it's not the transmission! YAY! Great news to me. However, the hesitation is still going on and it's only gotten worse.

The trans guy said he is 70 percent sure it's the catalytic converter. So my husband takes it to a muffler shop and he tells us $189 out the door...but he wants to spend a couple of hours looking at it to make SURE it's that. To me that screams him trying to get more work out of us and more money. I started looking up other things and I see that a bad O2 Sensor can cause the same problems. So then we feel we are at a cross roads. Do we get a new Catalytic converter or do we do the o2 sensors? I don't have a ton of money to do both and I don't want to do the wrong one

So we were talking to a friend and he says sounds like it could be a clogged fuel injector...OY! So he said put some enzymes in the gas tank and rev the engine to get it through there. So we put it in and we drive home. My husband was accelerating and the car just wouldn't shift and it was at 3000 RPMS and all of a sudden our Check engine light starts blinking. We get home and he pulls the codes and he has 6 codes.

P0449 times 2
P0302
P0404
P0420 times 2

He cleared the codes and the check engine light went off. He took it for a drive and came back and shut the car off. I decided I was going to take it for a ride and when I started the car the check engine light was back on. I took it down the road and came back and he pulled the codes again and all of those codes were gone except for the P0449 times 2.

So I guess my question is I was wondering if those 6 codes could have just been because the car just wouldn't shift at that time? they have went away but I read that a flashing light is bad. The problem I am having is that I don't have the money for my car to be sitting in a shop for days. I just want someone to tell me if it is the Catalytic Converter or the o2 sensor..or the fuel injectors. How do I find a mechanic who is going to be honest with us? And not take us for a ride? Isn't there a way for them to tell us what the problem is without us having to spend a ton of money first? I do believe it is one of those three things. I just don't know which. As far as the catalytic converter...there is no rattling that I can hear while we are driving..and there is no rotten egg smell. We just have horrible gas mileage and the hesitation while accelerating. Please help! Thank you!

 

Ejkemildner, just a thought, search the topic "diagnosing cat. with temperature gun" years ago I had a possible cat. issue and was able to test it taking temp readings at a few places, the temp gun shoots a red light and gives a temp reading wherever it hits, not expensive. Fran

 

Drive a Venture, not an Uplander, but...

P0449 = evap system (that's on the gas tank)
P0302 = misfire cylider 2 (that will feel like hesitation)
P0404 = EGR failure
P0420 = catalyst efficiency

These are all items that are important to fix before they cause other problems, but if you clear the codes and they don't all come back you will need to look towards the performance to see what must be done.

Regarding the catalytic converters, Fran mentioned 1 good test and those infrared temp guns can be picked up for $20. Obviously no rattling means it hasn't broken up, but that doesn't mean it isn't clogged which will cause most of what you mentioned although I'm not sure what caused the "no shift" problem.

"Cleaned the MAF"...a bad MAF could cause the engine to run too rich which could create some of those problems as well, especially poor mileage.

Does it ever blow smoke? How are the valve cover gaskets?

Honest mechanics can only be found by word of mouth.

 

sounds like a plugged catalytic converter,usually a catalyst efficency code means a plugged cat.if you drive it long enough with a missfire it will damage the cat.usually it will break up inside or start to plug up which will cause the issues you are having.it will also set maf codes due to the engine not being able to perform properly due to a plugged cat.i know im late with my answer but i thought i would still respond.