2001 TJ 4.0 missing and jerking really bad

[motorpig]

OK, a couple weeks ago I replaced my water pump when it went out, and the clutch too within the same week. I haven't had any problems for two weeks so I don't think any of my current problems are related to a loose wire or anything.

Yesterday while running about 50 mph my jeep just cut out for a split second and quickly picked right back up where it left off. It continued to surge like this once every mile or so. I got home and assumed it was possibly my coil pack going bad, No error codes or anything though. I changed my coil pack out in about 15 minutes to one I already had on the shelf, but It didn't fix my problem. Decided to keep driving it in hopes that it would eventually throw a code. I decided to run some seafoam through it just in case it was some bad fuel, to no avail. Today, it is much worse, jerking every 20 seconds or so. RPMS drop rapidly almost like turning the engine off briefly and right back on within half a second. I am thinking its possibly one of my upstream O2 sensors and have them ordered, but still not sure since I have no error codes. I did hook my scanner up and ran some tests while driving. I don't have a clue as to what I'm looking at on the majority of these tests results. I'm hoping someone can look at this and tell me what might be the problem.

Test drive at 50 mph:

MIL STATUS OFF

ABSLT TPS% 32.6

ENG SPEED (RPM) 1708

CALC LOAD 22.0

MAP (HG) 20.7

COOLANT (F) 190

IAT (F) 117

IGN ADV. 28.0

ST FTRM1 % -5.5 (Short Term Fuel Trim)

ST FTRM2 % -4.7 (Short Term Fuel Trim)

LT FTRM1 % 4.7^ (Long Term Fuel Trim)

LT FTRM2 % 3.1 (Long Term Fuel Trim)

VEH SPEED (MPH) 50

FUEL SYS 1 CLSD (Fuel System 1 Loop)

FUEL SYS 2 CLSE (Fuel System 2 Loop)

02S11 (V) 0.740^ (O2 Voltage Bank/Sen)

ST FTRM11 % -6.3 (Fuel Trim Bank Sensor)

02S12 (V) 0.660 (O2 Voltage Bank/Sensor)

02S21 (V) 0.700 (O2 Voltage Bank/Sensor)

ST FTRM21 % -5.5^ (Fuel Trim Bank/Sensor

02S22 (V) 0.660 (O2 Voltage Bank/Sensor)

OBD2 STAT CA (OBD 2 Status)

Anyone know much about this stuff? I went out a little bit ago and was holding the motor on about 1500 RPM and was watching the "FUEL SYS1" and "FUEL SYS2" reading. I noticed as soon as the motor started missing they both went from showing a numeric, to showing closed. If its not a O2 Sensor, could it be my Crank Position Sensor? I obviously had it off when I changed out my clutch. Thank yall for any help.

 

[glowell222]

There is a way to test the crank position sensor with a multimeter, though you will need to search it as I don't have it off the top of my head. I assume you have coil packs as well? I believe the OPDA has a sensor too, though I may not know what I am talking about on that, since mine has the old fashioned distributor. I don't think it's an O2 sensor at this point.

 

[motorpig]

There is a way to test the crank position sensor with a multimeter, though you will need to search it as I don't have it off the top of my head. I assume you have coil packs as well? I believe the OPDA has a sensor too, though I may not know what I am talking about on that, since mine has the old fashioned distributor. I don't think it's an O2 sensor at this point.

I do have a massive oil leak at the back of my motor and the oil runs right down on top of where that sensor is mounted. I've been wondering if that could be the issue. I just went out there and sprayed a lot of degreaser in that area, hoping that may be the issue. I've was about to change the darn gasket out this weekend but don't even feel like messing with it till I fix this issue.

 

[glowell222]

In the past when I have had a bad cam or crank position sensor, there was a code thrown for it.

A water pump and a clutch nearly simultaneously. Damn.

 

[Bsulzberger]

Does it only happen when you reach 3,000 RPM or is it at any RPM?

 

[motorpig]

Ok, I went out after degreasing all that and it didn't change anything. I was running a live test with my scanner and did notice something each time it stalled out really bad. It did it 4 times in 1/2 mile. I was watching the O2S22 (02 Voltage Bank/Sensor). Every single time is missed the voltage on the O2S22 dropped to zero. So, does that appear to be my problem?

 

[motorpig]

Does it only happen when you reach 3,000 RPM or is it at any RPM?

Really any RPM

 

[motorpig]

In the past when I have had a bad cam or crank position sensor, there was a code thrown for it.

A water pump and a clutch nearly simultaneously. Damn.

I know, luckily I already had a water pump on the shelf too. It never started leaking until the throw-out bearing went out. I could hear the bearing and looked under the jeep to find water coming out the water pump. I assumed I was hearing the bearing in the pump but it was actually the throw-out bearing. I was so mad when I cranked it up and could hear the throw-out bearing still roaring. But at least all that's behind me hopefully.

 

[motorpig]

Ok, I went out after degreasing all that and it didn't change anything. I was running a live test with my scanner and did notice something each time it stalled out really bad. It did it 4 times in 1/2 mile. I was watching the O2S22 (02 Voltage Bank/Sensor). Every single time is missed, the voltage on the O2S22 dropped to zero. So, does that appear to be my problem?