When I start the XJ for the first minute or 2 it runs a little rough and if you put it in gear and give it gas, it cuts out real bad. Once it idles for a minute or 2 it will smooth out and then it runs great.

Any ideas?

 

Wow. Thanks for the offers on ideas.

 

Gotta be patient, especially when you post up a thread on Friday night.

What have you checked so far?

FYI it sounds like you have a leaking injector.

 

Lucky if you get any ideas now seeing how you are.

3

 

1. I agree that a leaky fuel injector is a possibility. When there is raw fuel in the cylinder, it can take a little time to burn off the excess fuel. And it will run rough when doing so.

2. Checking fuel pressure never a bad idea. 96-01 should have 49 psi.

2. Never overlook tuneup hardware. How fresh are your plugs, plug wires, distributor cap and rotor??

 

No smoke on startup, so there shouldn't be excess fuel in the cyl.

Cycle fuel pump 3 or 4 times before starting and same thing, so the rail pressure/fuel pump is ok.

All standard tune up stuff is new.

 

Best to not assume and to verify with a fuel pressure gauge. I've seen "weak" fuel pumps with this symptom where low pressure is exhibited on startup and then it levels off and is close to spec. And you don't have to have smoke at startup when you have a leaky injector.

A fuel pressure gauge and 20 minutes of your time and you can verify all of the above.

 

check your oxygen sensor and wires.

Might have to pull it and clean it and see if that helps.

You could also unplug it and then see how it runs on start up.

If it runs better it's the sensor.

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What ever you do don't use the on board diagnostic system it might eliminate things its not.

 

 

That is the first good suggestion yet. I was wondering how long till someone suggested something helpful instead of throwing out random useless ideas like "check o2 sensor"

 

Have you checked fuel pressure yet?

What year is your XJ?

TPS, IAC, MAP, CTS, and IAT are all suspects. The fuel air mix is going to be too lean or too rich, until either the engine actually warms up and can run like the sensors are telling it to, or closed loop is entered and input from the O2s fixes whatever is wrong.

Once you get tjwalker's suggestion out of the way, if the problem still exists, clean all of the connectors to the above sensors and make sure your grounds are good. You can find test procedures for the various sensors on here with a search, results depend on year.

Also get the stick out of your *** if you want some help, chief. This is a free forum.

 

From Joe Peters and well stated. Sounds harsh but just makes sense:

"Let’s play a game.

You pretend that you are the only one that knows what year/engine/model, etc that you are asking about.

We will all pretend you never asked a question until you provide at least the bare minimum of information about your vehicle".

 

lmao. so true. . . had the same exact symptom on my 00. replaced #3 injector and runs like a beaut. they can get heat soak from the block . .btw. . . bein a dick heres gonna get you nowhere except for shunned. Just some friendly advice

 

Scanned it and no codes. Nothing showing up on the live scan while it's running either.

In case anyone didn't look at my profile to see what year and engine and such since I filled it out when I registered, it is a 96 4.0 auto.