I have a 2007 Taurus SE. When I get to 10-15 MPH the RPM's will shoot up and it will kick in very hard. To the point it jerks. It doesn't do it at any other speeds.

This has been going on now for 2.5 years. It was giving a code related to the catalytic converter so I had $1700 worth of work done in May 2014. It was fine for about 2 weeks and then it was right back to what it was doing before the work was done.

There is no rhyme or reason to when this happens. It does not do it every time I drive it. I can go weeks without this happening. I can spend all day Saturday running errands, stopping/starting at traffic lights and it won't do it. The next day I can make one trip to the bank and have problems. Or it will do it all the time for weeks on end.

It does it year round regardless of weather/temperature. I thought maybe it was related to bad gas from a particular gas station so I kept track of when/where I got gas and that doesn't seem to impact it at all.

The check engine light is on almost all of the time. It does go off occasionally for a few days and then it will come back on. The guys at Autozone say the code its giving now is related to the catalytic converter. They said that could be any number of parts though.

I figure it can't be a transmission issue or it would have died on me by now.

I'm afraid if I take it to a transmission guy to look at they will, of course, say it's a transmission issue.

I don't have money to continue to throw at it based on a "it could be".

Any one ever encounter this? TIA.

 

Can you provide the code(s) that were found?
Also what kind of work did you have done ?

 

In May 2014 I had the catalytic converter replaced. As I understand it there are two parts/components to the catalytic converter. Of course it was the more expensive one of the two. I remember the mechanic telling me something about it has platinum in it and that is why it was so expensive. I also had them do a tune up while they had the car.

I stopped by Autozone today and had them run the codes again. It said the following:

catalyst efficiency low-bank 2
Explanation
The oxygen sensors monitor the catalytic converters ability to store oxygen.
Probable cause
1 - Catalytic converter defective (failure possible due to items 2, 3 or 4 below).
2 - Engine misfire or running condition
3 - large vacuum leak
4 - Engine oil leakage into exhaust-valve guide seals, piston rings

When the catalytic converter was replaced in May 2014 the car ran fine for about two weeks. The mechanics did not notice any issues with oil leakage. I have not seen any signs of oil leakage either. I would assume if I was leaking oil somewhere I would be going through it and/or there would be a spot on my garage floor.

When I tell mechanics what the car is doing and ask them if the catalytic converter could be causing the jerking at 10-15 mph no one seems to know for sure or believe that these issues would make the car jerk like it is.

 

I can appreciate you posting the explanations for the codes, but I would appreciate it more if you were able to provide the codes themselves.
Just off the top, try this , when coming to a stop, place the shift selector in neutral and see if you still get the jerking.

 

My apologies. I'm not used to reading the print out that the store gave me. This is the first time deciphering the print out so I had to have the store help me find the exact code. The code is P0430.

So I can better understand what I'm doing/hoping to achieve....why am I putting the car in neutral when I come to a stop? I'm not having an issue when I stop. My issue is when I start. For example, I'm sitting at a traffic light and the light turns green. I accelerate from a dead stop. When I get to 10-15 MPH the RPM's will shoot up and the car will kick in really hard to the point it jerks. It does not do this at any other speed.

If I am to try putting the car in neutral as I'm stopping to see if I get the jerk, at what speed should I put the car in to neutral?

 

I suggested the place it in neutral because I couldn't tell from your post originally that it was occurring on acceleration. If it only took place on decel than it might have involved the lock up converter.
It sounds like a problem with the 1-2 shift. That is a trans problem.
The P0430 is related to a bank 2 problem that the oxygen sensor for that converter is indicating a problem that the converter cannot clean up or is reporting misinformation to the powertrain computer. A quality scan tool is required to examine certain information that should help isolate the problem area. This is one of those times guessing is useless. An experienced shop should be able to help pin down the shifting problem which could involve shift solenoids or worn parts in the trans.