Hi,

i just come back from a 1500 km trip,

After like 2 hour running i notice that my car was "missing fire" like if it was the lockup engage and disengage, but it was minimal miss.

First i tought my tranny was going out, arrived to my destination i let things like that.

The day after i took my car to go see old friends and when i start to move( like 1200-1500 rpm) it was missing just a little again. So ive decided to give it a try at WOT ,..

at high rpm i was clearly "missing fire"(dont how call it in an other way) and i noticed my boost was a little bit lower, and the car was feeling like i had the stock pulley...slower

(it happen to me earlier at high rpm while doing a run on quarter mile, but not frequently)

ive changed my wires before the trip thinking that it was the problem(missing on drag)

That same day (on my trip) i noticed more several miss , still between 1200-1500 rpm on small load and at WOT.

next day (today) ive decided to come back here, the car start good, smooth idle , but again when begin to move it miss , but very minimal miss,

the thing is that as long as i run it became worst and worst, at 2000 rpm with minimal load it was ok, but when trying to pass a car , the car shifted earlier in 3rd because it was like i released throttle.

anyway i continued my run and i got to climb a big hill and needed to pass a truck, so i open throlttle between middle and WOT was ok but as soon as i got in boost it was beginning to miss again and when ive looked back a huge dark brown smoke was going out of my exhaust...

At that point i was hoping no hill and no car to pass, 2 hour later im home .


Can it be the fuel filter? i hope

ill begin with that tomorow.

Any help will be appreciated.

Loss of power under boost...

Could be a couple things. Weakening fuel pump, or fuel pressure regulator come to mind. Maybe ignition coils.

Can you get the fuel pressure tested?

mmmm, ill try to get a fuel pressure test, but right away , only dealer come to my mind, but i hate to go there, $$$.

ive got miss even not in boost, but was worst as i push harder on pedal.

rolling at 50-55 mph i was getting minimal miss at like every 3 minutes.

tryed the car again few minutes ago, after the start ,the car is hard to move at low rpm(1500rpm)miss frequently , but if i give more gas its ok, it come easier after 2-3 minutes.


And the inside of my tips are black. Normally there is nothing.
I know it can be normal after long trips, it is supposed to be more brown than black.?

Maybe your MAF is crapping out?

i just do a search on google and found a forum , they were talking about o2 sensor and their effect, the car was a grand am, and the guy tell that if the o2 sensor near the cat is bad the car will run too rich , bad fuel mileage..

but rogue told me that sensor have nothing to do with fuel mixture, what i believe.

But... i had a very, i mean very bad fuel mileage, the worst ever. And i noticed that the first " miss" i got at the drag was after my cat was installed. May be just a coincidence.

Can i see if the front o2 sensor is bad? i mean is it difficult to know?

edit: and for the MAF , anyway way to check it?


Mike

can a bad plug can do that?

i changed them 3 month ago.


Anybody home? :?

The front 02 sensor helps determine the fuel mixture. The rear just determines if the cat is operating and does not affect how the car runs.

If you take the front 02 out, is it covered in soot? Something is making the car continually run rich.

If you take out the plugs, are the kinda brownish? Good. Or are they white (lean) or blackened (rich). Do they all look the same?

Thx jwikoff99

Ill take a look at everything i can check myself.

I hope its nothing too bad.

I've had 2 oxygen sensors go, one shortly after I put it in, the replacement about a year later. The engine would do strange things at times, that could be described as a miss. It seemed to me more like the engine had stopped running for a short time. Backing off on the throttle, or punching it would take care of the problem for the moment. It was quite intermittent. It took until the CEL came on for me to figure out what the problem was the first time. By the second, it was familiar. I had read here to stay away from Bosch. My local parts supplier carried Borg/Warner, so I tried those. I've now gone back to the AC/Delco.