BlueRidgeMark

Here's the story/symptoms:

1. I bought this 4.0 '97 Cherokee Country in May. Just under 200k miles on it then, 215k now.
2. When I bought it the Jeep had just passed emissions/safety testing.
3. CEL came on a couple of weeks later. Codes read 300 (random misfires) 301 (Cyl 1 misfire) and 304 (Cyl 4 misfires).
4. Rough idle started a couple of months ago, then hard starting when the weather got colder. A few pumps on the pedal before starting is sometimes needed to get it started, and I need to feather the gas pedal to keep it going until it warms up. It may stall otherwise. Seems to run fine at speed. Once warm, it sometimes idles high (1200 or so) when I come to a stop.
5. I cleaned the IAC & throttle body (took the TB off the vehicle completely; cleaned the whole thing.)
6. I replaced the TPS. Why? What testing told me to replace the TPS? None. The stupid thing came apart on me when I pulled the electrical connector off! Small parts went flying. Ooops. Off to Autozone for a replacement!
7. I also replaced the plugs and coil. The old plugs were some funky gimmick three-prong junk, so they got replaced with Champions. (The old plugs looked... decent. An even dark brown.) The coil is from NAPA. The rotor & cap look good, and the wires look new, like they'd been replaced recently.
8. Today I did a fuel pressure test. 47 pounds or so, but the needle bounces quite a bit when idling. (Between about 42 & 49 or so.)
9. With the engine off, it's a solid 47 pounds, which it holds for 15 minutes, then it starts dropping. It's @ 32 psi @ 30 minutes.

I don't yet have the FSM. I tried buying one from an online source (www.pacificcoastmanuals.com) that was recommended in a thread I found here, but their site didn't process the transaction. Gave me an "Ooops. That didn't work. Try again." message. It's such a flaky looking site that I'm a bit leary of trying again. Visions of credit card fraud are dancing in my head. Can someone vouch for them? Or recommend another source?


So, any suggestions as to where to go next?

michaelrayb1

I'm having the same problem with my 89 jeep Cherokee Laredo . iv done all the cleaning also and replaced the map sensor but the problem persists...please help!

BillyBoy

Was having the same... issue after issue... replaced the cps, map, cleaned the throttle and iac, plugs, wires, coil, changed the cap and rotor, cleaned all the grounds, couldn't get anywhere with every check I could do... kept getting different code after different code. I had, by all research, checked everything any normal guy could...

I gave up, brought it to a dealer, they took about 20 minutes to find it was some wires at the back of my engine {monster harness} that had dryed/cracked/desinigrated... they changed 4 of them, and 160$ later, all is well.

Just saying, beat your head against the wall long as you can,but if your intel isn't matching up, worst case scenario, occasionally going to a mechanic isn't as painful as you think, and... there's absolutely NO way I would've found that, no matter how much I checked.

Good luck.

TheGreatGazoo

I had the same problem with my 89 Cherokee. I found a small crack in the vac line going to the MAP sensor. I could not believe such a small crack caused such noticeable problem. I replaced that vacuume line and the thing ran awesome. for the heck of it, 2 weeks later I replaced all the hard vac lines I found 2 more cracked going down to the ball next to the battery.

BlueRidgeMark

Hmmm. That's worth looking at! It is getting progressively worse, so that kind of thing would fit...

No chance to look at it again before Saturday, but I'll let you know what I find.

Thanks!

Roler

Here you go, your pre97 FSM.
Go to right side of page, scroll down a little bit, under AJOR Community.
http://www.ausjeepoffroad.com/forum/vbindex.php

BlueRidgeMark

Thank you!

Hmmm. There's a pre-97 and a post-97, but nothing for 97!

I'll download both and figure out which one is right.


Thanks again!

Ugh. And today the trans started slipping once it got really warmed up. Had a hard time just leaving a stoplight. Had no choice but to keep going for a while because I was in D.C. and there was no place to pull over. Found a parking garage and let it sit for a couple of hours while I had dinner, and it was fine once it cooled down. By the time I got home it was slipping again.

Aarrgh.

BlueRidgeMark

Well, that all became moot. Trans is toast, as I suspected. The shop found the right frame rail is almost rusted through near the rear wheel, and a few other problems. I'm looking at way more than the car is worth to fix it all.