pittman71

1997 XJ 4.0 auto. Thought it might be TPS after testing it when it would max at 3.8 on the middle wire Swapped in another TPS and no change. Fuel pump runs. Made sure it had pressure at the schrader valve on the fuel rail but dont have a gauge to see how much. Prior to this, engine would occasionally buck/stutter and sometimes stall but start right back up. IIRC, if a CPS is bad, it just wont start at all?

Anyone know what it might be??? All info, ideas or suggestions are greatly appreciated. Been searching quite a bit. Thanks!

freegdr

When pushing gas pedal to get it started your adding air not fuel just too let you know. Fuel is controled by ecm and injected. Have you cleaned Iac yet ?

pittman71

Not yet. On the list though. Thanks for the reply and confirmation.
Do you know if dirty IAC would cause it to buck/cough and or stall while driving?

tjwalker

Assuming there is no check engine light? If you've ever seen one, even if it isn't on now, retrieve codes with a code reader or a scan tool.

1. Gotta get that fuel pressure tested so you're not chasing your tail. I'm not saying that is what it is, but I am saying that it is one of the first things a tech. would do if you brought it into a shop. For a 97, you should have 49 psi, plus or minus 5 psi.

2. Be sure that your battery passes a load test so that it isn't giving the engine management system fits with low available juice.

3. And of course, when symptomatic it's always a good idea to review status of tuneup parts. Fresh Champion plugs gapped to .035, quality plug wires, distributor cap and rotor.

OldTires

This was my issue when my battery started acting up. Could only keep the idle going if I stepped on the gas pedal.

EZEARL

When my IAC gave it up I lost fast idle and had to work the pedal to start. Otherwise I had no problems. BUT maybe yours is worse off than mine was.

pittman71

No codes at present. Any way to check since it is stuck in my garage and I don't have a reader? Will do on the pressure test with gauge asap. Might start with the battery as it was low from sitting and I've had to jump start it when trying to getting running. It has kept its charge if I drive it more regularly. Tune up couldn't hurt.

pittman71

Thanks for the info everyone! Will be checking the battery and cleaning the IAC for the short list. Will report back.

pittman71

Ok, battery failed load test so I put in a new one. Started right up and ran! Then stalled after idling about a minute. So battery was definitely at least part of the problem. I'll be cleaning the IAC and throttle body as soon as time allows. Hopefully that will get rid of the other issues.

OldTires

Did you have the alternator tested?

Kogulanathan Kasinadan

might be IAC...

Cane

how do your battery terminal look? i was always skeptical of the "clean your battery terminals" advice, seemed too simple to work and cause the issue, but I did it when i had the same symptoms as you and now it starts right up every time.

I had to clean the battery cable thoroughly too, they were pretty crusty.

mburgess33

Check and clean up your ground cables. I had a similar problem a few months ago and haven't had any problems since.

pittman71

That's a pretty good video, thanks! I'll use it to test the alternator later. Had to pull the battery and bring it to Advance to have it tested so didn't get to check the alternator at the same time. I'm the IAC/throttle body cleaning now.

pittman71

Yep. Had that happen to me in the past as well. Been pretty diligent about it ever since. Terminals are in good shape.