The surging could be from a bad TPS.

 

I've been thinking about replacing it. I was actually wondering if the champion coppers might be to blame.

I just filled up on gas and the fuel pump, apparently, still thinks I have a quarter tank of gas in it. That obviously isn't working right. Maybe it was just the fuel level sending unit. Until I get the time I'm just going to continue to use it and monitor it. I'm going to try putting the stock plugs back in place and seeing if the champions aren't happy with my MSD 6AL.

I'm running the ACCEL super tune kit from quadratec with the 8MM spiro-feral core wires... with the MSD 6AL ignition. I'm not sure which spark plugs came with that kit, but they weren't ACCEL as advertised on Q-Tec. I think they were NGK's.

A question I have, does it matter via model year whether you use champion coppers or NGK?



Side Note: Putting the IATS back in the stock locale didn't make a difference.

 

As far as plugs I have never really noticed any difference in any of my vehicles.I am on my first Jeep and still have it torn apart so I cant really comment on jeeps preference on plugs really but just going by my experience with other vehicles just get a good set of plugs or at least use what the manufacture recommends.
I feel that NGK are a quality brand of plugs and run them in my motorcycle as well as my other vehicles. If you can spend a few bucks find some iridium plugs .

As for the TPS what I said is from experience as well and not just a guess. I had a 91 jimmy s-15 with the 4.3L engine and it was surging real bad,it would run fine going down the road and all that but it was hard when it came time to stop because it was pulling so hard, not a good thing on snow and ice so I put a new one in it and it was good to go.
You may be able to test the TPS but I am not sure. I know they can be a bit pricy so if you can find a way to test yours before replacing it I would try that out.

For your fuel sender issue make sure all grounds are good and the wires and connectors too.New senders are a good sized investment.

I am not sure about the other things you mentioned but tuning a vehicle with aftermarket parts is kind of an art imo lol.You just have to try things out and find what works best for you.

 

x2. Exactly what I was thinking.

 

I put NGK plugs in my pickup, i wasnt too impressed...after about 10k miles, on 2 the ceramic cracked and was loose in the threading causing an exhaust leak

 

Was talking to a buddy of mine at work a week or two ago...his Chevy Malibu had some similar problems...and, like you, he replaced his fuel pump and fixed the rough start issue, but had all kinds of problems with the engine running too rich...after a week or two, he had what we all describe as a "Homer Simpson" moment...when he realized he accidently swapped the fuel line connections at the fuel pump...he was pumping fuel to the wrong end of the fuel rail.. DOH!

I'd hightly suggest checking the fuel pressure with your new Airtex pump. Previous post here from TJWalker:

"Put a gauge on the fuel rail. You should have 49 psi, plus or minus 5 psi for your 98."

You also indicated that your fuel level sensor isn't working...so its possible that something got messed up on the re-assembly. I wouldn't go too far solving new problems until you're pretty confident that the fuel system is working A-O.K.!

Good Luck!

 

I'm starting to think it's the plugs now. I can smell what seems like slightly burned gas fumes any time I come to stop.

Something else I notice... when I come to a stop (at any time) between the 15-3 MPH slowdown phase the rpms drop to 500'ish. As soon as I come to a dead stop it goes right up to 750 and idles there. It also hesitates on take off when I give it throttle.

And while it's idling... it's relatively rocky. Like every other 1/2 second I can feel the whole vehicle kind of bouncing with the motion of the uneven idling of the engine. I wonder if maybe having just one spark plug of a different brand is causing that.

Sometimes I wonder if the guys at the counter at A-zone get me the right parts. I asked for the sparkplugs and a coolant temperature sensor. He gave me 5 plugs and a MAP sensor.

The MAP sensor is more expensive so I didn't bother with it since they only gave me 5 plugs and I'm wondering now if they were even the right ones.

Then again they might have given me the wrong pump for all I know. I still haven't verified the part number. Time to google.

I'm about to go plug in the old plugs and see what happens.

 

Did you gap the plugs or did you buy them pre gapped? Always gap them yourself... honestly from what your describing it sounds more like a fuel problem then spark plugs.

 

I gap them myself.

I just pulled the plugs. O M F G are they black as night. Black as night. I put the old plugs back in and cranked it up. It was throwing droplets of black carbon out the back like it was screaming S words with a horrible lisp.

And the bouncy idle got more pronounced as well. I hooked up the DTC'er and pulled "No Engine Messages", "Ignition Coil not a Primary Circuit" (that's been there ever since I hooked up the MSD), and now I have... P0171, Engine Bank 1 Lean.

I don't understand how it's lean when it's tossing liquid soot out the exhaust.

Any ideas what a loads of unburnt fuel for about 40 miles would cause to happen?

BTW, never using champion coppers again with my current ignition setup. The shiny color should have been an indicator. I bought bosch platinum's a while back and immediately junked them after I put them in. My engine ran like crap with those, and these champion coppers are the exact same sheen of shiny'ness. Since others use it with no problem I'm going to go ahead and say the 6AL with the ACCEL 8MM spiro-feral wires don't agree with them.

 

Change the front o2 sensor. If it is running that rich, and reading lean, got to be a o2 sensor. Just a guess, but bettcha it fixes it.

 

Damnit. That bothers me. I just bought that 02 sensor. It's brand new. How about I just... clean it off...

 

Lots of things would cause a lean or O2 sensor code to come up, it does not mean the sensor is bad it just means the exhaust is lean at that sensor.That is the job of the O2 sensor.
Check your fuel pressure,map sensor TP sensor also another that has not been mentioned is the idle air control valve.

 

I already have a new idle air control valve on it.

Ok, so I bought new plugs and an 02. Upon taking out the new 02 I had just put in there with the new plugs... it was black as night too. Covered in soot.

So I ran a can of seafoam through the brake booster before I put in the new plugs and 02 sensor. It smoked like a chimney. I put another can in the gas tank before I did that.

After that I put in autolites with .055 gap (supported by my MSD ignition). After that it ran fine... with the exception of the slowing down portion. It still drops kind of below 750 and has a hard time staying alive when I slow down, but as soon as I come to a dead halt it goes right up to 750 and idles like nothing happened. Any clues on this??

Also, I bought a new TPS and it didn't make a difference. So I have a new IAC, TPS, and MAP.

Note: There's no criss-crossing fuel lines on the Cherokee, at least not in the 97 and later models. It's dummy proof.

 

Glad to hear your gettin it sorted out man

 

I'm stumped. Wish I could help more. I thought for sure the tp sensor would take care of ya. Was vacuum leaks covered already? maybe throttle body gasket?