Weird issues.

I have a 99 XJ, 2 door. Ill give yall a little history on it first.
I had to replace the engine in it. Well the engine that I replaced it with didnt have the 99 head on it. (Just bought a rebuilt longblock and dropped it in) Now if it is idling and I roll the windows up or down I can watch the volt meter drop. I have an aftermarket headunit, sub and 600watt amp in there, but I have had that setup in a previous car without any problems.
Also sometimes when I pull up to a stoplight after just starting it up, the idle will drop really low, then come back up and run fine. Along with that, after i start it up if I am driving along sometimes I will hit the gas pedal and it seems like it doesnt want to go anywhere. Then after a couple of seconds of running like that it will pop and take off and run like nothing is wrong.

Bit more info:
I replaced cap, rotor, wires, plugs (all around 7k ago) Didnt replace the coil though.
Put new Ford XF2E-C4B injectors in it, and it cleared up for a little bit, but now its back. I havent checked fuel pressure... Should do that though.
Anything else that you can think of that would make me have this problem?

Have you checked the ground wires from the engine to the chassis?

I am planning on doing that today actually. I do know that my manifold is cracked, and it is not throwing any CEL

i973eat1 said:

.. I do know that my manifold is cracked, and it is not throwing any CEL

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Why not fix what you know is wrong and see if the other issues clear up (since they are often ralted to O2 xensor issues, including cracked manifolds) ?

Well, I bought a knockoff APN header off of ebay, but it wouldnt fit unless I dented the tube or shaved the intake down a ways. I havent had the money to buy a different one. I cant see spending $500 on a header, but it looks like that is what I am going to have to do....

Also I was trying to get ideas of what other people think of my issue too.

I usually weld up cracked stock headers and stick em back in. Even if it breaks again in 20k miles, I'm out a few hours to swap it, a $7 manifold gasket, and maybe 50c worth of fluxcore wire. Haven't had any break again yet.

That is all fine, except for the fact that I think every time that I weld up a crack another one forms. lol Also Where all the tubes come together right before the collector is cracked through the center of where the tubes come together.

i973eat1 said:

That is all fine, except for the fact that I think every time that I weld up a crack another one forms. lol Also Where all the tubes come together right before the collector is cracked through the center of where the tubes come together.

Click to expand...

FIX the problem--the XJ flexes too much and has too rigid of an exhaust system.

Put a section of SS flex hose between the downpipe and the front CAT.

http://www.exhaustdepot.net/flexsection.html

With the flex section installed you will no longer get those cracks at around the collector.

I have installed 2 APN and just one needed to have the intake manifold slightly ground to have it fit. It took about 4 minutes to fit them together, locate the interference, and to grind for 20 seconds.


Your issue could be anything or nothing. You won't know, or be able to reliably troubleshoot, until you fix any known problems.

Wait, so, it took 4 minutes? I am sure you must have researched it on the internet for at least 30 hours, and will need several hundred in specialty tools to do that.

It could be as simple as a gunked up connector, I've had strange idle issues caused by those, but the header should probably be fixed before you try to diagnose it further.

As far as the electrical issue goes, xj's have a somewhat weak electrical system to start with. I'd do a big 3 wiring upgrade and see if that helps. A capacitor never hurts on a big system either.