My car has just had a 180,000 miles major service. Rear brake pads and right rear brake caliper replaced. 

A couple of days after the brake warning light (amber) illuminated filled by a steady traction control light.

That's when the engine became 'lumpy' like it was running on two cylinders. I stopped the car to text the garage that had done the service. However, when I restarted all warnings were gone and the engine was normal again.

Later that day, I had a repeat of the first incident with the same outcome.

Other Monday I drove to work, the brake warning light illuminated, I waited in trepidation for the traction control light but it didn't come on.

At work I had a diagnostic test done on the car, but the only code was for the No1 fuel injector. 

As I have driven the car more, there have been no more lights. However, in the Mersey tunnel yesterday on the uphill part the engine misfire on three occasions. The traffic in the tunnel was heavy and slow. One out of the tunnel and on the motorway, it didn't miss a beat, and I pushed it hard to see if I could get a repeat. 

Everytime I get in the car now, I am expecting the worst. Can anyone explain the strange issues?

I don't know if a car of that age has an OBD port. If it does, get it scanned on a decent code reader.

At the same time it would be worth getting the battery professionally tested. A dying battery can cause false warnings and interfere with the ignition system.

Hi Cliff

I don't know if my car has an OBD port. I work in a college and motor vehicle plugged in a code reader into some sort of port. They tend to have the latest gear, so I expect it was a decent reader. I can ask them to check the battery on Monday however.

I wondered if because the car has had no service history for a very long time, could changing the air filter cause the ECU to recalibrate it's fuel air mixture?

See this:

https://www.audiownersclub.com/forums/topic/29630-constant-tone-when-engine-started-but-no-dash-warnings/#comment-124249

 

Hi Cliff

I am not getting any of the weird warning lights anymore. However, from time to time and not everyday, there is a misfire. The one in the Mersey tunnel as previously mentioned, and again this morning. But only a couple of times at high speed.

I think this does point to the No1 injector breaking down. My question now would be, if I need to replace one injector, should all four be replaced at the same time?

From what I have read on the forums if one injector needs to be changed it is well worth changing all of them, but I am not entirely convinced injectors are the real problem. It needs to be scanned on a proper code reader capable of diagnosing your particular car, not just what the college happens to have.

The college has massive sponsorship with Toyota who have a factory just down the road.

Their cars are brand new Toyota's straight off the production line and the equipment donated to the college is the newest and best tech available.

If the diagnostic test states it's the No1 injector, then the No1 injector it is.

As you wish. Please let us know the outcome.

Hi Cliff, the outcome is this fault simply went away. I had another posting regarding an oil warning light on the 10 April. This turned out to be a pressure sensor, even though the check button stated oil level fault. However, when the diagnostic test was carried out, there was no faults on anything.

My theory! The car had just had a 180,000 miles major service. The fuel and air filters were both replaced as part of this, the mechanic did say, it looked these hadn't been changed in a very long time, if ever. If the ECU had been operating on restricted parameters, then suddenly those parameters change. Could this be the ECU getting use to it's new operating parameters. The car runs like a dream now and there is a marked difference in the performance since the service.