repollo

So Im lost here since there isn't much I can debug from the computer 'cause I dont have a scanning tool. The car starts smoothly when is cold with the revs at 1000, maybe 1100(probably it is not adjusted properly). When I depress the throttle the car revs smoothly after 200 milliseconds of pressing the throttle, in the first 1/5 of a second the car almost struggles to rev.

Now the real issue starts when the car has warmed up, the car may fail, like is a bad piston ring, or like a spark plug is not connected. When trying to accelerate the engine may stall or may rev up really badly. If you are in the Drive position the car will backfire, will stall for sure, will not accelerate and the more you press the throttle the more the engine revs lower but really slowly.

Thats almost about it, if I used may, is because it is not going to definitely do that but probably will since the issues are really inconsistent. I tried working out the engine harness connections and they seem to be okay. If you guys have any starting points, I will really appreciate it.

jdowen2

Sounds like the timing belt is off a tooth or two. How long have you had the car and when did trouble start?

repollo

I just got the car, was just wondering if anyone had any idea, since Im thinking about buying the car. The owner told me the engine was rebuilt or change, not sure, I know it must been tethered with since the connectors are a little fussy and out of place, still I was thinking about the timing belt, but cold start idling sounds and revs perfectly to be the timing, the belt ALWAYS makes the engine fail. Anyways Ima get a scanner tomorrow and see whats off, since I kept debugging and the problem seems to be somewhere at the intake stage. I'll verify the belt timing but I don't think is in there, but let's just be sure, right?(Gonna buy you a beer if its just that)

Anyhow anything I tried seemed hopeless until I disconnected the battery to erase all the DTCs that were stored in the ECM/PCM.

Once it was all clean and tidy, connected battery and:
I started the engine and waited for it to come up to temp, then started disconnecting different sensors at the intake, the MAP does not seem to be the issue, it revs down and comes up back to defaults but engine fail still around. Then decided to disconnect the IAC valve, and this is where I noticed that the engine started to rev nicely and perfectly like a brand new car, I then decided to leave it like that and try to change tranny positions, it drove perfectly for a minute and it started with engine failure again like it did not have power or something. So I decided to go back to debugging and disconnected the fuel regulator vacuum line, it worked better but something is quite not right.

Tomorrow Im getting two different scanners and a fuel pressure gauge and see whats up inside this car. So until then if anyone has something else that wants to add, I greatly appreciate it!

EDIT(1/15/13@2300): I just found out this,

cleaned it and it revs nicely, only thing to verify is the pressure and DTCs when I start driving the car, I guess is gonna rev perfectly where it stands right now since all the dirt in the tank wont move until I lower the car from the slope is now on...

Ill update tomorrow when I get my readings.

repollo

Couldn't get the fuel pressure gauge, but scanners said it was all good no problems, tried to make the MIL come on again with no success, I drove for more than 30 minutes, turned the engine off and on again again, to see if the MIL came on, nothing. Before I cleaned the fuel filter last night I noticed that the "fuel pulsation damper" was opening and closing the little screw it has on it, and after I cleaned the filter it does not pulsates anymore, so my guess is that the whole issue is in the fuel tank since there is like some kind of debri in there. Im not sure how the fuel pulsation system works and what it does, if anyone can shine any light on that would be much appreciated. Ill try to find out how now, anyways until next time. I believe that for now this case is CLOSED!