Strange problem, do I need a re-tune?
06-23-2009, 08:14 AM
#1
Staging Lane
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Location: Cleveland, OH
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Strange problem, do I need a re-tune? Hey guys.
Now, I don't know the first thing about tuning, and really, I'm pretty new to working on cars. Last summer I did some mods to my car, including a new cam, intake and headers. After I finished the mods, I took the car and had it tuned.
The car ran fine for the last 6 weeks or so of the season last year, and ran fine until about mid May this season (about 6 weeks). A few weeks ago, the car started acting funny. It doesn't seem to idle as well, and it feels like it's lagging from a start. I feel like I have to give it more gas to get it moving. It's worse if the car is somewhat warm when I start it, like if I took it to the store, let it sit for 30 minutes, and get back in to go home.
It also seems that the exhaust isn't as "raspy" as it used to be, or that it doesn't have as much high frequency noise in the exhaust when it's running (not that I mind, but it doesn't sound the way it did).
At first, I thought it was a problem with the air system. I replaced the filter, cleaned the MAF, checked the stock TB, and after that, the car ran "right" for a day, and returned to the somewhat laggy state.
I've put some Lucas fuel system stuff in the most recent tank of gas to see if maybe part of the problem is the injectors, but I don't really expect a whole lot from that.
When I re-did the engine, I removed the AIR system, so it could be the cats are getting clogged, but would that really happen in less than 2000 miles?
I'm kind of out of ideas. Can a car "lose" it's tune? I would figure it was flashed into the computer and is there until it's removed, but before I did the engine mods, the tune on the car was very odd, and neither I or the previous owner had ever touched the computer.
If that's unlikely (which I'd have to believe it is) do you have any other ideas of what could be the cause?
Thanks in advance.
Now, I don't know the first thing about tuning, and really, I'm pretty new to working on cars. Last summer I did some mods to my car, including a new cam, intake and headers. After I finished the mods, I took the car and had it tuned.
The car ran fine for the last 6 weeks or so of the season last year, and ran fine until about mid May this season (about 6 weeks). A few weeks ago, the car started acting funny. It doesn't seem to idle as well, and it feels like it's lagging from a start. I feel like I have to give it more gas to get it moving. It's worse if the car is somewhat warm when I start it, like if I took it to the store, let it sit for 30 minutes, and get back in to go home.
It also seems that the exhaust isn't as "raspy" as it used to be, or that it doesn't have as much high frequency noise in the exhaust when it's running (not that I mind, but it doesn't sound the way it did).
At first, I thought it was a problem with the air system. I replaced the filter, cleaned the MAF, checked the stock TB, and after that, the car ran "right" for a day, and returned to the somewhat laggy state.
I've put some Lucas fuel system stuff in the most recent tank of gas to see if maybe part of the problem is the injectors, but I don't really expect a whole lot from that.
When I re-did the engine, I removed the AIR system, so it could be the cats are getting clogged, but would that really happen in less than 2000 miles?
I'm kind of out of ideas. Can a car "lose" it's tune? I would figure it was flashed into the computer and is there until it's removed, but before I did the engine mods, the tune on the car was very odd, and neither I or the previous owner had ever touched the computer.
If that's unlikely (which I'd have to believe it is) do you have any other ideas of what could be the cause?
Thanks in advance.
06-23-2009, 09:29 AM
#2
You can pressure check the cats. I don't know where to get it, but there is a tool you can get to screw into the 02 bung to measure pressure. Sounds like a possible vacuum leak too. You didn't lose your tune. Logging the car would help isolate the problem as well.