This is my 2001 stock xj, I've had some problems with this in the past dying or having a hard time starting after dying. In the past when this triggers I'll be driving and it's like the truck dies/becomes unresponsive, the electricity will still be on but when I give it gas it doesn't rev.

I replaced the CPS, TPS, cleaned the throttle body but still it pops up like today. The biggest symptom when idling for a while it will start to run real rough/shake and then typically die. When I try to start it back up and give it gas it doesn't rev at all, as if the gas isn't getting to it. I see some people talk about heat soak, but would the no rev also be part of this?

I have zero insulation on the fuel line/injectors so might be the problem, but I live in CO and it's cold right now.

Next steps?

 

This doesn't sound like heat soak to me. It sounds more like you are running out of fuel. Have you checked your fuel pressure?

As an FYI, the heat soak issue for me occurs mostly during hot summer days. If I shut off the engine after it is at full operating temp and then attempt to start it again about 10 minutes later it will idle terribly. It will still rev, however also terribly. It clears up in seconds however, and is not a continuous problem like you describe. it is a small window for this to occur, if I restart it in less than 5 minutes, or more than 15 I have no issues.

 

Did you clean the IAC while you cleaned the TB?

 

Just cleaned the IAC again today, it looked fine since last cleaning. Do I pull that spring part of it down and clean in there too in the IAC?

Today I pulled out my scanner and the cel wasn't on but got the code p0303 which says 3rd cylinder misfire so...heat soak likely?

The feeling I am describing causes a pit in your stomach, you press down the gas and no response. No revving, no higher rpm, just silence.

Have not checked pressure, I'll do that when I get some gauges.

Any reason to think it's the TPS?

also I had previously changed both the crankshaft and camshaft position sensors any reason to think it's either of those? When I had swapped the camshaft it fired up but died soon after. I changed the crankshaft PS and seemed like it was ok, but maybe the problem never was truly solved as it's back.

One last thing, I have a backup ignition coil pack, is it necessary to swap this in given the "3rs cylinder misfire" error?

 

When my TPS went, the Jeep idled poorly, but when I pressed the gas it was fine. It didn't shift as smoothly, and I had a CEL that identified the TPS.

 

Put in new heat wrapping on rail.
Swapped new TPS (though it then threw a code p0123 and p0122 about throttle position sensor "circuit high" and "circuit low" I assume since I swapped them. Cleared code and it didn't pop back up.
Now we wait and see.
Also checked fuel pressure, was about 45 at idle, and only went down a few points after a few min.
When you accelerate what should I go up to? Didn't seem like it went up much but I didn't try long.