Hello All,

I purchased a '94 XJ a couple of months ago and I've been having some problems recently.

When I was driving around town last week, I rounded a corner, and my engine cut out. It cut out so smoothly that I didn't even notice until I went to put in some more gas. It started right back up, so I drove it to a shop nearby and they told me that the issue was spark plugs, ignition wires, and my distributor cap and rotor. I thanked, and paid, them for the diagnosis and then replaced all of those parts myself, but the problem persisted.
Often, when I take my foot off of the gas at a complete stop the engine stalls and cuts out. It seems to be a problem with my idle. If I put it in neutral and rev it to about 1300 RPM, the engine will stay running smoothly, but when I let my foot off the gas it will stall/cut out. When it dies, there is no sputter or weird noise, it just cuts out very smoothly. This makes me think that it would not be a fuel issue. This usually happens once the engine is warm, but has happened before when it is cold. From reading all the posts on here that I could find, I see some common causes of a similar issue: crank position sensor, dirty throttle body/IAC, throttle positioning sensor, MAP sensor, or a bad battery/related wiring.
I bought a CPS from O'Riley before I found out that they aren't the best, and can sometimes even be bad out of the box. Then, I test drove around my block for about 20 minutes, fully stopping and accelerating, and it seemed fine. Until I drove it the next day and it cut out right as I came to the first stop sign in my neighborhood. Could the new CPS be bad out of the box?
Then, I read that a dirty IAC/throttle body could cause problems like this, so I cleaned it out. This gave the same impression of working during my test drive until I drove away the next morning and it cut out at the stoplight.
Today, I tested my throttle position sensor with a multimeter and found that it spread from 0.78, with the throttle closed, to 3.54, with the throttle all the way open. I couldn't find the correct voltage, so this may be the cause but I'm not sure.

I'm trying to diagnose the problem without just throwing parts at it, but I'm having a hard time figuring out what to do next. I tried to include as much information as I have, to help with the diagnosis. There is no check engine light, but I haven't scanned for codes because I don't have an OBD I scanner.
I appreciate any help or advice you guys have!

 

Make sure your intake manifold bolts haven't loosened up. Put a wrench or socket on every one of them. Easiest if you remove the air box.

Have you ever cleaned your throttle body and IAC?

 

Hey Cruiser54, I did clean the throttle body and IAC. I did the key on off trick and got the codes: 11, 12, 24, 54, 55

from what I see:

11 No ignition reference signal detected during cranking OR timing belt skipped one or more teeth; OR loss of either camshaft or crankshaft position sensor.

24 Throttle position sensor over 4.96V

54 camshaft sensor/distributor timing



Do you have any ideas about what I could try first? I have already replaced my crankshaft position sensor. I will tighten the intake manifold bolts.

 

Those codes are pointing to cam sensor in the distributor.