First time poster here.
I got my 2001 XJ Sport in 2016 at 145k miles. Now at 156k. Ran like a champ for a year and a half. As I noticed I had 3 cylinder misfires (ugh), I got a new ignition rail and spark plugs and that seemed to do the trick.
However, ever since I did that my car WILL NOT stay alive unless I have my foot on the gas. It will rarely start without me even giving it gas. Every red light I come to I have one foot on the brake and one on the gas, slowly revving it so it wont die on me.
Pretty much any time I start it, it gets close to 200 RPM. My XJ usually idles around 600-700 RPM.
I've cleaned my Idle Air Controller. I've had the battery and alternator tested. I've cleaned the battery terminals from gunk/corrosion. I've dumped fuel cleaner in my tank. I'm stumped. This used to be my daily driver. Any tips at ALL will be appreciated. I need my car to work again.

No check engine light or codes.

I don't know if I'm posting in the right category, let me know.

 

IAC might need replaced even though you cleaned it.

Found this test for it in some notes. I know it worked on my '96 in 2014.
IAC contacts:
A
B
C
D

A to D =40-80 ohms
B to C =40-80 ohms
B to A = open
C to D = open

Mine tested border line but it worked. I eventually replaced it a year later with one from SMP.

 

Definitely make sure your battery is in tip top condition. I had the same problem when my battery was going. Would not start without a lot of foot on the pedal. Would not idle without feathering the gas. Would buck on acceleration. Replaced the battery and all the problems went away. Had it again on my '98. Battery was marginal and it started doing the same thing. I have had a lot of different vehicles and have not had one more temperamental about battery condition than the cherokee. After seeing it on 2 different cherokees and reading the same thing on the interweb forums, I would definitely check it. Clean all your battery cable connections and check ground wires.

 

Thanks, I was thinking I should get a load test on my battery. Started fine this morning a few seconds until i started driving. I'm gonna get it checked out and I'll let you know what I find.

 

I'll take a peek. Thanks for the reply.

 

Update. My battery was originally rated at 700 amps. Right now, my battery is only pushing 500 amps. Can that really be the problem? The guy at the battery shop told me that would be plenty to start my car. I don't know.

 

Sounds like it's a real possibility.

I'd try to get my hands on a new battery that's returnable (or a known good one) - hook it up real tight to the cables and see if it starts and runs fine, then you'll know for sure.

 

I got my 2006 Dodge Ram I could take one from. Know for a fact has both great batteries. I'll let you know

 

Another update.
All fixed.
Took apart my throttle body and cleaned the hell out of it.
Yeet.