88cherokeepyles

So, the jeep is 3 months old to me, 154 k on the engine. I figured it was time for a tuneup, so I started with spark plugs, no problems there. Then I did the rotor and cap, plug wires, and fuel filter, and now it's starting to run a bit funny. The engine is a bit shaky at low speeds, just fine mid range, but above 65 mph it feels like it shakes a lot more. The only thing I can compare the feeling to is when I ran the thing to fumes last week and it puttered into the gas station just in time- meanwhile making a bit of a sound and shaking.

Also noticed a little knock that seems to come from under the driver seat, but very rarely.

Also should note that the fuel pump is really getting loud and old.

Anybody have a recommendation as to why it would run worse after a tune up? I'm taking a big trip this week so hopefully someone can help out.

Radi

Did you keep the old parts? If so...swap them back in one at a time and see if the problem disappears. It isn't unheard of for new wires to have defects, caps/rotors to be defective..

macgyver35

X2

Solid advice there. I once (in my early 20's) had a '78 CJ-5 that had 64K original miles and was in amazing condition. It was a military spec'd unit that I got from a retired Sargent. I did all the standard tuneup stuff, and for a few weeks things were fine. Then, it started missing and sputtering, and progressively got worse over a couple of weeks. Drove myself crazy trying to find the problem. Turned out one of the brand new spark plugs had a cracked porcelain and was shorting to the head.

Weeks of frustration over what was, at the time, a brand new $1.27 part.

Radi

Maybe it's just creeping old-fartism, but it seems the quality control of this stuff just isn't what it used to be. (yeah, yeah...walked to school..no shoes... it was winter all year..uphill both ways..)

I've gotten more bad parts in the last 5-6 years...plugs with bad seals, wires with bad crimps, alternators that don't, sensors that appear to be molded by PlaySkool...
Keep the old stuff until you're sure the new stuff is actually better.

Az Survivor

Puppies die too. It's that simple - just because a part is new doesn't mean it isn't defective. I've learned to never rule anything out.

XJ Stryker

Start with you fuel filter.

You new
One
May be defective

cruiser54

Absolutely positive the firing order is correct?

rrich

Firing order got switched?

What plugs did you use - the ones called out on the underhood label or the wrong "trick" plugs the kid at the parts hose gets a commission on?

ZINGGG

My thoughts exactly.

Best place to check before replacing parts again

XJ Stryker

Yeah yeah yeah I overlooked it.

88cherokeepyles

Alright, thanks for all the suggestions. I changed plugs first, when it was not starting. Ran quite good, but decided to do the tuneup...

At first it wasnt bad - that's when I posted this. I took a mega trip, probably 700 miles, and on the return home, all of the sudden, the thing would start lurching whenever it went uphill, just like it was when I was out of gas. Wouldnt go more than 30 up hills, and on the highway I could only go 55.

My fuel pump has been whining for a long time now, but recently it goes much louder, and wavers in pitch a lot. My unknowledgable idea is that the pump is about to give up on me - it wont allow fuel to get to the engine when it has to work hard.

Any advice? It may be one of the tune up parts still, the one thing I didn't try replacing with the old part was the fuel filter. The new one ran much better than the old going up steep hills when I initially changed it. I don't have the old.

Plus side is that I got 24mpg on the way back from my trip - roof basket with spare tire, big fat guy in the front seat, and a lot of camping gear in the back.. Incredible mileage but it ran like crap all 7 hours of the last leg.

freegdr

1988 replace the pump napa has the whole aasembly 100 bucks plug and play

hankthetank

Ya probly pump. But I noticed you didn't say what brand of plugs, and whether or not you checked/adjusted gap on those new plugs...

88cherokeepyles

Plugs I believe were bosch, copper ones. Gap .035, like I have seen all over this forum.

Also I checked the firing order and it is correct.

So, where might I find instructions on how to install said Napa whole assembly pump? I am fairly new to car stuff.. I do have some buddies that could help me, though.

freegdr

very simple jack up jeep let rear axle hang down jack stands under frame unplg pump its right in front of rear axle,take off lines tap lock ring loose from around pump pull out old reverse for new make sure your below half tank fuel...