2000 Limited, 4.0, NP242, AW4. This one has the distributorless ignition, which may or may not be relevant.
Here's the problem: chugging on cold starts at idle until it warms up (around 180degF or so). Not so badly that it stalls, but badly enough that if you try to drive it while cold it has the classic symptoms of timing being off: pinging, misfires, foot to the floor and no acceleration or climb in revs (engine bogs down).
Fuel economy and response when warm are about the same as they've ever been - makes sense, given that this is only a cold start problem.
I've run an OBD-II scan on it: no codes are stored.
The 'cylinder #3 misfire' recall common to 2000s has been performed per the VIP report.
Searching suggests the IAC and/or throttle body could do with a cleaning, which sounds like a reasonable first step. Having killed a TPS on a different XJ before this doesn't feel the same, mainly because the problem only happens when cold - dead TPSes are noticeable all the time in my experience, so I'm loath to suspect it.
Is there anything I may have missed? Anyone else who's dealt with this on a 2000 have any words of advice, specifically on the cleaning? I'm getting ready to make a Kragen run to deal with this, so advice would be most appreciated.
Here's the problem: chugging on cold starts at idle until it warms up (around 180degF or so). Not so badly that it stalls, but badly enough that if you try to drive it while cold it has the classic symptoms of timing being off: pinging, misfires, foot to the floor and no acceleration or climb in revs (engine bogs down).
Fuel economy and response when warm are about the same as they've ever been - makes sense, given that this is only a cold start problem.
I've run an OBD-II scan on it: no codes are stored.
The 'cylinder #3 misfire' recall common to 2000s has been performed per the VIP report.
Searching suggests the IAC and/or throttle body could do with a cleaning, which sounds like a reasonable first step. Having killed a TPS on a different XJ before this doesn't feel the same, mainly because the problem only happens when cold - dead TPSes are noticeable all the time in my experience, so I'm loath to suspect it.
Is there anything I may have missed? Anyone else who's dealt with this on a 2000 have any words of advice, specifically on the cleaning? I'm getting ready to make a Kragen run to deal with this, so advice would be most appreciated.