Just resolved a similar problem on '03 Forester 2.0 turbo. Car would not respond for 2 to 3 seconds when the accelerator pedal is pushed. Also, when it finally kicked in it lacked power. I did not take it in until check engine light came on for O2 sensor...p0171... After explaining problem to mech he said it was either the fuel pressure regulator or the fuel ...
The stalling issues point toward problems with an engine control system (air, fuel, or spark), but again short of replacing the fuel pump, you have already replaced the parts most likely to cause those issues. The idea that the car will act normally on short trips is also strange.
The problem that stands out to me is that the car has trouble accelerating, ...
Sounds like trouble with the idle speed control valve. On the '93 Miata, it looks like this:
This little guy, when working properly, will let enough air into the engine to keep the engine alive when you are not using the throttle. Sometimes they get dirty, sometimes the connector gets loose, sometimes they breakdown and need to be repaced.
Here's what you ...
Platinum is going to work best in this application, because platinum will stand up to the rigors of the LPG better. Iridium would work even better. There are several other types which would work even better, but if cost is a main factor, platinum will work pretty well.
There are other considerations you need to take into account, though, as well. I found ...
You probably need a new lambda sensor. Here's why:
You're right - the lambda sensor needs to reach a certain operating temperature to function properly. Until it reaches that operating temperature, the engine ECU will assume open-loop operation and not rely on the sensor's signal to determine whether the engine is running rich or lean.
Your tests and data ...
Good example of PID graphing.
Consider the possibility that these symptoms are caused by a mixture issue instead of timing. The STFT is adding fuel and the symptom of hesitation further suggests that the mixture is lean. It is likely that if O2(B1S1) and INJ PID's were included these would show a lean O2 with a corresponding lengthening of injector on time....
It sounds like you got a bad batch of fuel and have some water in your fuel tank.
You can use a fuel additive with alcohol in order to get the water 'mixed in' with the gas.
You can also put the highest octane fuel in your car and try and drive through it, results may vary.
Your local auto parts store can recommend the additive they carry to get the water ...
The average gas engine exhausts between 1 and 1.5 CO during normal combustion at stoiciometric mixture (lambda 1.00). The catalysts is expected to burn this excess CO. So if there is .6% at the tailpipe then the most likely cause is a catalyst that is either not lit or the mixture is out of the catalysts working mixture range. The farther the mixture gets ...
The data doesn't support it
You measured your coil resistances to be within spec
You measured your wire resistances to be within spec
You've already replaced the plugs with ones that require less voltage to operate
So while the bad-coil theory may explain what's going on, I'm not confident it will.
Possible explanations for the readings obtained
Off the ...
I have a 2007 Outback that had the same symptoms. Taking the MAF (Mass Air Flow) Sensor out and spraying some electronic sensor cleaner on it removed the hesitation. There are just two screws that hold it in to the intake, so it is a quick operation.
Not sure if long term the MAF needs to be replaced but for now it is holding up.
There are a number of reasons why a car can hesitate when accelerating at low speeds, however bogging down is typically due to the engine over-enriching or leaning out.
Rich or Lean condition
Typically bogging down at low RPMs happens when the engine goes too Lean or too Rich suddenly (too much fuel, or too little fuel).
Since your car is fuel injected, ...
Listen to cranking the engine when cold. If uneven, compression is bad (unlikely, but you must rule it out before spending any more money).
Check vacuum lines, especially the PCV valve hose and grommet.
Replace the PCV valve itself.
Replace the EGR valve.
Once removed, spray carb. cleaner through the PCV and EGR ports in the intake manifold (they often clog)...
I find it hard to understand what is really going on from your description.
But my guess would be something electrical.
I suggest checking:
alternator, belt, pulleys
crankshaft & camshaft sensors
Post more info and I will edit as well.
That combination of combustion issues could indicate dirty/worn throttle body or IAC (as mentioned by SteveRacer.)
The "turbo lag" symptom makes me think something is stuck in a way that restricts airflow.
Inspect these to diagnose, listen around the engine bay for hissing sounds that could indicate air leaking as well.
For such a new car, I would ask the dealership to fix the problem. There is probably some form of warranty. If it's over, you may have luck with basing your requirements for fixing the thing on consumer protection laws.
But I would assume based on the problem that it may be related to ignition. Is there any error code? New cars will usually detect such ...
So, that's not what is generally meant by a "boost leak" – a boost leak is on the compressor side of the turbocharger, compressed air that should be going into the engine is leaking out before it gets there. What you have is an exhaust leak before the turbo charger.
That said, I don't think your exhaust leak would cause the behavior you're describing (but ...
A stumbling engine should result in abnormal engine vibrations. It should be possible to use the knock sensor(s)/misfire counter to detect abnormalities.
Note that it will not be as straightforward as setting a simple threshold-based limit since the normal sensor readout will be heavily dependent on factors like engine speed.
Quite often surging like this is caused by not enough air getting passed the butterfly valve in the throttle body when the butterfly is closed. Under normal circumstances, there should be a very small gap around the butterfly to allow the air required for idle. If the butterfly is closed too much, the revs will drop too far forcing the engine ECU to open ...