BajaRunner

My jeep grand cherokee was driving down the road and all the sudden an occasional miss started, like 1 miss every 5 minutes. I stopped went in to run an errand and came out, started it, put it in reverse and it died. almost didnt want to start back up. Barely made it home chugging and trying to die. I get home and its idling perfect. A friend of mine says his did the same thing and it was a crank position sensor. I figured what the hell, put one in, and did a tuneup(plugs,wires,cap,rotor). Initial start ran fine, then died, did the exact same thing.

Got a code reader, and heres what i have

1. PO351 Ignition Coil A Primary/Secondary circuit malfunction

2. PO740 TCC Circuit Malfunction

What should i do from here?

1996 Jeep Grand Cherokee, 4.0 inline 6, automatic.

Thanks

epeek

Chry products have had alot of problems with their ignition
coils. Replace the ignition coil, most likely its
failing. They can act up intermittently. The tcc code is a
trans torque converter code. Could be caused by a bad torque
converter solenoid. You have to test for power at the solenoid.
should have power with key on. Computer commands the ground
to the solenoid. Just a simple trick to see if torq is engaging.
drive down th road in o/d at about 45-50mph. lightly tap the brake
pedal with to accelerator holding steady at speed. If the tack jumps
up about 200 rpm,you know the torque is engaging. It could be
a old code if the trans ever got low on fluid. You cant check key
cycles with a code reader. If you need to get more technical, let
me know.

cig1988

Try the pickup coil in the distributor.

BajaRunner

So which one should I replace, ignition coil or pickup coil?

Liberator21

I had gotten a similar coil code on my 96. It came when I was towing my boat up hill, but I didn't have the misfire. It turned out to be a bad oxygen sensor at the cat. You can also check codes by cycling the ignition key on and off 5 times, leaving it on the fifth time (without the engine running). The check engine light will flash the codes, and the odometer will display them as well. A 55 means end of codes.

epeek

Pick up coils are no longer used.The were on older
vehicles before they went to cam & crank sensors.
Code 351 will only set when pcm detects peak coil
currant was not reached in 2.5 milliseconds of dwell
for 3-6 seconds.It will also only set when asd relay
is energized. The ecm will only trigger the asd relay
if it has a proper crank signal & sync. coil primary
resistence is .95-1.20 ohms. secondary is 11.300
to 15.300 ohms. 99 % its the coil,could be wiring
from coil to ecm,but not likley.

BajaRunner

damn, sure sounds like you know what your talking about
Ill pick up a coil and put it in tommorrow. My friend said his crank sensor did the same thing to him. I replaced that, then checked the codes

JJONES

reset the ecm and retest,once a problem is sent to the ecm it is stored there,sometimes it wont affect drivability depending on the code!with all those codes set it is possible they were intermittent!with the retest,this will narrow down your actual problem!emc stored codes will cause the parameters of the engine to change!the emc(computer)will retard the timming and richen up the fuel system so untill it is reset!this limp mode enables you to safley get off the road and to a tech for repair!if continuious driving is done in this condition aka(with the check engine light on),you can do some more damage than the original problem,burn out cat,burn out o2 senson,clogg erg ports in the manifold ect!leaving the gas cap off for three starts can even set your emc into limp mode!i would reset the ecm,drive car until light comes back on and then with your tester youll find your problem and eliminate the intermittent codes which probably happened while driving under limp mode with check engine light on!if i had to through parts at it though with out dianosing it,i would go with the crank angle senson or cam sensor,which ever one onyour vehicle is used to tell the ecm when to fire each plug!good luck!

FOUNTAINATLAST

Crank sensor failer is common on these Jeeps but so is a dirty throttle body that will cause it to die at idle or idle very poorly. Check the throttle body if its dirty clean it out and reset the idle through your scanner or disconnect your battery to relearn the pcm.

epeek

Guys,did you read his first post? He already put a crank sensor
in it! Same problem. His symptoms are consistent with a bad coil & the coresponding code.
By the way,if the crank sensor or cam sensors go bad,the
ecm will detect it being out of sync and ALWAYS set a sync
code. Thottle body crud will cuse stalling,but not off idle. He
said he was driving when it started to skip. definetly not a
throttle body issue.