1995 Toyota 4Runner, 4WD, 165k miles, automatic - mild rough running 5-10 mph, and at 40 mph (on occasion) there will be a shudder, and a few times at 70mph it feels like a flash-stall where there is
no engine stated, but you did hit most parts, unlike most post here.
does the check engine glow when the engine misfires.????
that is misfire, (shudder)!
ever give it a real 60,000 mile interval tune up, by the book, yet?
that is what it is misfiring or bogging, bogging is just extreme misfire.
its intermittent ,which means the shop wont find it. (most likely).
what i do is connect my scan tool and log all the major PIDs and DTCs. to file. then when it messes up.
i go home and play back my log file.
bam there it is. Clear as mud. right..
Im going to assume this is engine problem and not tranny slip.
STALL word, key.:
this is where OBD2 excels, finding determinants.
and nobody seems to use it.
here are some examples. (in each case , so can it be wires and connections, no need to repeat that mantra.
1: lost comms. the ECU just lost 12vDC power, (fuse and power feed issues, (more test to do , ask how)
2: MAF dropped to zero air flow (gee its bad or the wires to it are bad)
3: ECT dropped out , ditto
4: IAC, dropped out , or TPS went nuts.
5: you were cruise 40mph and the 02 front sensor when ape sh't
6: at cruise. and P0301 hammered the memory. injector 1 wire loose.
301, spark plug 1 , cracked insulator.
301, intake valve 1 , stuck. (more freq, oil changes are needed.
7: P0300s, the fuel pump (or friends) decided to go to 10 psi, for kicks and giggles. or lean DTC codes.
log the DTCs driving,
and look for pending fails.
the logging of sensors give you a signature of the failure.
its a very powerful tool. that few dealers use. (right)
sorry you have intermittent. the internet bleeds with them.
they are for sure very hard to find , blind. (pre 96 cars are mostly blind)
for DC power problems, i use my logging voltmeter.
and win. every time !
if not , out comes my logging DSO..... but only rarely....above gets 99%
Feb 12, 2014 |
Toyota Cars & Trucks