Hello everyone...I am at wits end with this little car and if I had hair I would pull it out......
1996 Toyota Corolla
1.6L DOHC EFI
I was driving to work the other day and the engine light come on/flashing and it starting skipping/shuttering really bad. I drove it back to the house, and had the codes pulled from the computer.
The following codes appeared:
P0300 - Random/Multiple Misfire Detected
P0302 - Cylinder 1 Misfire detected
P0303 - Cylinder 2 Misfire detected
P0305 - Cylinder 3 Misfire detected
P0305 - Cylinder 4 Misfire detected
P0105 - Manifold Absolute Pressure or Barometric Pressure Circuit (MAP)
P0120 - Throttle/Pedal position Sensor A Circuit
I have changed so far the Throttle Sensor and the MAP Sensor to no avail.
All plugs look good and all cylinders are getting spark, and all fuel injectors have been cleaned in an ultrasonic bath and seems to be working (I pull the connector off and the engine dies a bit)
So I am pretty much stuck right now.
The computer reader gives the following parameters at idle
MAP (Hg) 9
Ign Adv 8-12 depending on rpm
ST FTRM1 % 0.0
LT FTRM1 % -1.6^
Fuel Sys Open
O2S11 - .140
O2S12 - .060
I shot the Engine Control Module (ECM) connectors and the connectors that plug into it with some contact cleaner to make sure they were clean. And I seem to have noticed an improvement. I also took the cover of of the ECM while it was removed and didn't notice any abnormalities on the circuit board, it looks very clean.
When I drive the car now it still idles rough but now runs good at higher RPM's in first gear and in all other gears it seems to run smooth until I give even a little bit of throttle. Which also makes me think it's lean. I went ahead an changed the fuel filter after I ran the gas tank dry. I put in some fresh 93 octane and didn't notice a difference after the fuel filter R&R.
I checked the MAP sensor and TPS for voltage, both sensors ARE getting 5 volts.
I completed a resistance test of the TPS and the ohm values seem to have come out right. The only discrepancy is was when throttle valve fully open I got 2.9k and the limit was 3.3k-10k, but the reading did climb nicely and steady as I opened the throttle to full.
I check timing with a light and it came out ok, it was 12 but the engine was little above idle. Supposed to be 10 at 700rpm I got 12 at 790.
I still suspect a vacuum leak and I looked again today for like the 10th time and didn't find anything.
Any new ideas would be much appreciated..