1995 Toyota Tacoma misfire on all cylindars

MISFIRE2.7L

MEMBER
1995 TOYOTA TACOMA
4 CYL
4WD
MANUAL
230,000 MILES

1995 Toyota Tacoma 4x4 with 2.7L. Misfires on all cylinders at idle and throughout RPM range to about 3900RPM then runs fine on up to red line. Codes store for check engine light are: P0301, P0302, P0303, P0304. Have replaced ignition coil, rotor, cap, plug wire, spark plugs, fuel filter, pcv valve, pcv valve hose, took to shop said it could be possible fuel pump? Why would it have fuel at high RPM? Problem started after car washing under hood to remove mud. Started vehicle and check engine light flashed. Ignition coil gave it more power but could not correct misfire. Found out when I unplug the MAF sensor and start the truck the problem goes away. No missing what so ever, but I guess it runs it rich? Im not sure cause you can see black carbon coming out of the exhaust, so im sure its not good to run the vehicle with it unplugged as well as the gas millage is horrible with it unplugged. Tried new MAF sensor and made NO difference. Also doesn't miss for the first 5 secs after its started.

3 Replies

RASMATAZ

MECHANIC
75,992 POSTS

Test the coil and EGR valve also the alternator if its producing the correct output-Water is a conductor if it hits an electrical connector could short that circuit out

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Sunday, March 28th, 2010 AT 8:22 PM

MISFIRE2.7L

MEMBER
2 POSTS

Testing the EGR Valve is for sure the next thing I am going to do. Just replaced coil. I am assuming that the alternator was not affected since I have driven the vehicle alot since it has happened and never lost charge on the battery, or had the battery light come on. The misfire problem goes away when I unplug the MAF sensor, but comes back when I plug it back in. Tried a new re manufactured MAF, same problem thanks.