I have a 98 Sport 4.0

Ok so been having problems with my jeep stumbeling and stuttering randomely... I had my dad bring home a serious scanner from work....
ok heres the questions i need answers for...

Crank Postioning Count- Should this number be a steady number? Or should it be going all over the place on the scanner... mine goes from 4, 90, 140, sometimes up to 200.Should this be a steady number at idle??
Cam Positioning Count- Same thing Im getting readings all over the place.. Should this be one steady number at idle??Or should in flucuate??

Throttle Positioning Sensor- Should this sensor have any delay in it while on the scanner?? It seams to have a hesitation . at idle its at.76 and reving it up it takes a while for the numbers to resemble what the rpms are. I was told that this sensor should be right on with reving the motor, mine seems to stumble a little then reacts??


What Distributor Cap and Rotor do you guys recommend or have had success with on the jeeps???

TIA

 

no one has any info on this?? I find it hard to believe!!! Bump!!

 

all seams normal, the crank count resembles how many times its counted a revolution, counts to 200 or a set timer and then resets, same goes for the cam sensor, since its counting its working, the scan to tool should show the same rpm as the gauge...

the TPS has delay on scaners, why? it updates every so often and slower for some sensors the others, also the more data its showing the slowe rhtey will be... I wish it didn't, but all scanners i've used have had delay. I check the TPS with the key on, engine off. let off pedal. should read almost 0%, then I go half close to 50%, then floor it should read close to 100% (again engine off!) scan tools have delay as its showing you past info due to how fast the engine and computer adjust.

 

Ok thanks.. I been trying to narrow down the problems of why my jeep stumbles and bogs when i rev it up.. Ill try the tps with the engine off!!
We figured out yesterday that when we took the CCV Valve hose that runs to the intake manifold off and pluged the valve on the intake manifold, it ran alot better...Any reason to that?? Something isnt obviously working right for it to make my jeep stumble to the point it will shut off . Any idea's.

 

Sounds like you may have already found your problem. Vacuum Leak. I would start looking at all the vacuum lines and check them for cracks or maybe one or more of them have been disconnected.

 

Yeah after hearing that the sensors are intact and are working properly , we can narrow it down! I also realized that my downstream o2 sensor has only 2 wires. Not 4 like its supposed to.. Not sure what the up stream is like , but I will be checking.. Any idea what this would cause?? I drove the Jeep today and she was fine, no sputtering or stumbling... Im picking up a fresh cap and rotor today, checked the spark yesterday and it was a yellow ish color... thinking some water or moisture got in their.. hope to figure her out soon... I need to go hunting!!!!!

 

Ok well.. yesterday she ran great for like 30 mins total... But yesterday afternoon she ran like total ****.. I could hardly drive down my driveway and back with out it sputtering and about to stall when i give it gas... Checked all the sensor's, they are all good. Check all the air hoses , good to go... I even changed the distributor cap and rotor last night , nothing.. Something hasta be acting up here... Bc sometimes she will run great.. but most of the time its running like ****...So something hasta be shorting out or just working some of the time.. Is their anyway a bad downstream o2 sensor can cause these problems?? Kinda at a lost for words with this thing. Cuz it ran flawlessly before I swapped mufflers... Maybe I shuld a goddamn tail pipe on the thing and itll work.... HELP!!!!!

 

Kinda sounds like a faulty fuel pump. Check your fuel pressure at the fuel rail. A bad fuel pump will starve the engine of fuel and cause it to sputter, no power etc.

 

Also check distributor shaft for play. This was my culprit.

 

Fuel pressure at the rail is strong.. Not sure of the lb's, Im borrowing a gauge from my buddy today just to check.. I will check the dist shaft for play.. seeing that I replaced the cap/rotor lastnight... but I just went to grab some breakfast and took the jeep. And While waiting in the drive thru... my jeeps starts to act up... stumbling bad, idle is at like 250-500 rpm and stalled about 3 times.. I watched the volt meter, and while it was stumbling and about to stall , volt meter was crashing as it was stumbling... from 14v down to almost 0v...Im thinkin my battery must not be able to handle the load or it has a short at the ground causing a mis-fire.. Will be diagnosing this afternoon

 

Think I may have found the culprit.. think it was bad fuel!!! I put 6 gallons of 93 octane and Gas Dry and Fuel Cleaner let it sit over night last night and it rans great today!! hope this was my only probem... Just trying to burn off this old gas!!