Q7 4.2 engine problems please help!!!
10-16-2014, 07:19 PM
#1
Q7 4.2 engine problems please help!!!
Ok, around a month ago I started noticing no power from a dead stop when accelerating. I dumped a bottle of GUMOUT full fuel system cleaner in the gas tank and all this started happening. I can almost put the peddle to the floor and its barley moving, but when I go ahead and push it almost to the floor, it will kick in full throttle. Very noticeable to passengers like I want to go really slow and then stomp on it. It does this about 50% of the time.
The engine light came on, it ended up being a bank 1 misfire code. So I changed all the spark plugs, and that cylinder coil. Still no go, light came back on, and doing the same thing. So I took it to a shop, they pressure checked all the cylinders, and determined that it must be the fuel injector. So after $900 I now had a new cylinder 1 injector. Well a week later, symptoms back, engine light back on. Black smoke will sometimes come out of pipes upon starting sometimes. Oh and it only gets 11 MPG, no joke and that's driving like an old lady.
Now, It is bank 1 and bank 2 misfire. I was just told to try and replace the coil on cylinder 2. But they thought it was interesting that 2 and 1 are bad since 2 fires then 1 fires in order.
They are thinking that either the camshaft sensor is going bad (but no code?) or something is wrong with the computer. They did say it sounds like it could be a busted headgasket between cylinder 1 and 2 causing both to throw a misfire code.
Anyone have a clue here? I am about to trade it in next week and take a big hit and get a Lexus or Infinity. I am going to replace the coil on 2 this weekend and I might just take a big hit on the trade in just to get out of it.
What do you guys think? I am torn I love this truck. Well the way it looks...
Some have said to try seafoam in the brake booster.. I really need to get this fixed.
The engine light came on, it ended up being a bank 1 misfire code. So I changed all the spark plugs, and that cylinder coil. Still no go, light came back on, and doing the same thing. So I took it to a shop, they pressure checked all the cylinders, and determined that it must be the fuel injector. So after $900 I now had a new cylinder 1 injector. Well a week later, symptoms back, engine light back on. Black smoke will sometimes come out of pipes upon starting sometimes. Oh and it only gets 11 MPG, no joke and that's driving like an old lady.
Now, It is bank 1 and bank 2 misfire. I was just told to try and replace the coil on cylinder 2. But they thought it was interesting that 2 and 1 are bad since 2 fires then 1 fires in order.
They are thinking that either the camshaft sensor is going bad (but no code?) or something is wrong with the computer. They did say it sounds like it could be a busted headgasket between cylinder 1 and 2 causing both to throw a misfire code.
Anyone have a clue here? I am about to trade it in next week and take a big hit and get a Lexus or Infinity. I am going to replace the coil on 2 this weekend and I might just take a big hit on the trade in just to get out of it.
What do you guys think? I am torn I love this truck. Well the way it looks...
Some have said to try seafoam in the brake booster.. I really need to get this fixed.
Last edited by JoeIndy35; 10-18-2014 at 07:22 AM.
10-18-2014, 03:17 PM
#3
AudiWorld Senior Member
Seafoam or gumout will do nothing much, I am taking a guess by saying you have a really bad case of carbon buildup on the intake valves. Take it to a european indy who will be able to check it out, cause I doubt the fuel system is the problem.
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