Bought a 1988 Jeep Cherokee with 220,000 miles. It idles pretty nice, I don't hear water pump noises or anything else out of place. However, I got up on the freeway, and it started hiccuping and bucking. Pretty bad at some points. Later, drove it up a steep hill at 55 miles an hour, very little trouble, a little bit of a buck, but nothing as bad as when I was cruising along on the freeway. I had a Bronco II with a short in the ignition system that had similar symptoms, but would there be any suggestions where I might start looking to solve this problem?

All Help Greatly Appreciated,

 

Off hand I would say to change the spark plugs, wires, cap and rotor, then see what it does.

Recommend NGK ZFR5N or Champion RC12ECC plugs, gapped to .035".

 

**I agree with Ken; start with a tuneup. The importance of solid tuneup hardware cannot be overstated. Don't forget to change the fuel filter while you're at it!

**If you are still symptomatic after this, I'd test fuel delivery. Must be done with a fuel pressure gauge which can be rented inexpensively at many parts stores; call around for availability. For your year XJ, you should have 31 psi at idle. Then disconnect the vacuum line leading to the fuel pressure regulator and the pressure should jump to approximately 39 psi. Be sure that the vacuum line is not wet with raw fuel.

**Another possibility is the oxygen sensor. They have a finite lifespan and are oftentimes ignored. For your 88, either Bosch or NTK would be a good choice for replacement.

**Below is a link to some other things to consider. Good bookmark!

https://www.cherokeeforum.com/f51/cr...x-tips-153657/

 

I went out and did a quick inspection, and it would appear that the previous owner has replaced the plugs, the distributor cap, and maybe the plug wires. The coil doesn't appear to be replaced. All the fluids (engine oil, transmission oil) appear to be fresh. I've noticed a coolant leak at the reservoir and the curious metal 'T' joint that doesn't appear on my '94 and '95, but that's plumbing. Repairs are easy compared to diagnostics. I'll contact my local parts store and see about borrowing or renting a fuel pressure gauge. Assuming that the vehicle is reasonably well-tuned, what would be your next suggestion?

Honestly, All Help Greatly Appreciated,

 

Something else going on with this New-Jeep-To-Me: The speedometer needle bounces around as the vehicle accelerates or decelerates. It settles down for the most part once you're at speed.

 

Cowboy, click on the link in my signature and do the stuff outlined in posts 1 through 5.

 

Cruiser54,

Thank you so very much. I know what I and my minions will be doing tomorrow.

I wish I had recorded today, perhaps I should try it tomorrow, as now I'm working on a theory that The Three Stooges were either time travelers or could see into the future. At least some of their routines occurred spontaneously today as my two sons and I worked on this Cherokee. Not only were the stunts Pavlovian, but absolutely inevitable.

Could you suggest an electrical cleaner and where I might purchase it? My son might be more familiar, but the term isn't lighting off in my synapses.

 

No shortcuts from the minions. Larry, Curley and Mo need to put a real effort into doing those tips!!

 

Electrical contact cleaner is widely available; even at places like Walmart in the automotive section. Any parts store will also carry this. Brand not that important.

 

We spent most of the day cleaning terminals. Followed your four post suggestion, although I might go back and work some of them. I found a set of terminals underneath the coolant reservoir that either had corrosion or perhaps lithium grease on them. Cleaned them thoroughly. No symptoms have disappeared, but the bucking seems less intense. The engine dying: I drove uphill about three miles, turned around and came back down, cruising at 55MPH, most of the way not even having to gas it because its quite a steep grade. I turn into our driveway, braking and turning right. The engine died as I'm in the driveway. It has done that twice at the exact same spot, same circumstances.

Any suggestions?

All Help Greatly Appreciated,

 

So what EXACTLY have you done so far?

 

Besides following your four Pink Posts, I have replaced the Fuel Filter. The oil and transmission fluid appear to be new. The spark plugs and distributor cap appear to be new. The spark cables appear to be in good condition. The air filter could stand replacement, but its not that bad. I dumped a fuel injector cleaner into the tank as Nick, The-Guy-At-Pep-Boys-Who-To-This-Day-Bemoans-Trashing-His-Comanche-Ten-Years-Ago, suggested.

 

Look inside the dizzy cap.

I have seen wires that are not replaced in conjunction with plugs, cap etc go South as a result of being "disturbed".

 

I will check on that right now.

 

You say turning right you have tilt coloumn ? Read this.....https://www.cherokeeforum.com/f2/che...g-right-12981/