Damsels in distress

The damsels I’m referencing are me and my baby, a 1994 jeep wrangler, 4 cylinder, red with a black soft top, great attitude, sunny disposition… some of you around NYC might have noticed her Saturday night when she failed to maintain acceleration while merging onto the turnpike from the George Washington Bridge (that’s a left lane merge and thus absolutely terrifying to do at 35 mph)…

But the problem started well before that point… back up in MA (not pointing any fingers, but isn’t that where this show airs from?)- anyways, my jeep was having difficulties maintaining acceleration, which at first I accredited to the high winds and big hills I was driving through/up, but quickly realized as she began to backfire that perhaps it was not a surface problem as I previously thought. So giving up the excellent time I was making, I pulled off at the next exit to find some help and end up at a Gettys service station.

Perhaps the bongs for sale by the cash register or the teenagers making out in the corner should have scared me off, but my determination to make the finish line of my NH to DC journey overruled my concerns and I handed my baby over to one of the three attendants and proceeded to wait for them to check her out and also give her an oil change while they were at it… 2 hours later, the same guy comes out to report that I was low on power steering fluid and windshield washer fluid, but worry not he had fixed those things… not wanting to be dubious, but worried those might have absolutely nothing to do with my car’s acceleration issues, I inquired further with the man and he assured me that my car was good to go, so off I go…

But, surprise-surprise, a mere 10 miles later the car is acting worse than before I stopped… I limp my way into CT, backfiring gracefully every so often, and I stop again… it’s 5 pm on a Saturday so I figure I’m probably stuck in North Haven for the night, but the awesome guys at Classic Car Care (not a bong to be seen and genuine concern all around- they actually called and checked on me the next day) agree to take a look at my jeep and they quickly discover that the Gettys guys have put several extra quarts of oil in my poor baby (about 3-4 quarts too much) so they set about fixing that problem and change my now oil-drenched airfilter, but the best they can do as they aren’t a full service shop is to clean out my fuel injection system, which they do then they test drive her, and I test drive her, and she seems magically healed.

Thus we all very pretty good that I may make it to DC after all (and SC after that for the holidays), but alas after running perfectly for 70 miles, I found myself switching lanes on the New Jersey turnpike like my life depending on it (which by the way it did as did anybody else around me), making for the shoulder like a drowning man for the shore… as my jeep decides it simply cannot go on this way in 5th gear, 4th gear, 3rd gear… no acceleration to be found in any gear, so like a pitcher pulled from the game i the 5th inning, I managed to gimp my way off the next exit to lovely Ridgefield Park, NJ where I give up for the night and sleep fitfully with dreams of nightmarish merging racing through my mind.

The next day, Sunday, brought no chance of help as shops were all closed to I decide to limp down the backroads and have my triple A card ready. I take 78 across PA through Allentown to Harrisburg and drop down to 15, going 50-55 mph will no problems… all of sudden just past Gettysburg, right around the Mason-Dixon line, after 230 issue-free miles, my jeep gives up on a tiny anthill (barely what you could call elevation) in fourth gear going 40-45… same problem… failure to maintain acceleration, backfiring… engine feels like it’s not getting air or fuel, one of the two… I pull over as I drop down to 20 mph at Beckley’s Liquors and throw in the hat… Triple A very quickly towed me home from Frederick, MD to Bethesda, MD…

However, I have since taken my jeep to two shops and they can’t get it reenact the failure to maintain acceleration… any ideas out there?

Other important information:

my jeep is a 1994, 4 cylinder wrangler with 180,000 miles on her; I have had her since I was 16 (11 of her 14 years) and I’m the second owner- she’s the only car I’ve ever had so I’m very attached to her, nearly symbiotically bonded (though she seems to be mimicking the economy more than me at the moment); while she does have a lot of miles, she also has a rebuilt engine and recent events aside she is in great shape. The speedometer sometimes go out at the same time as the failure to maintain acceleration, but it also sometimes goes out when the car is acting fine (that is a recent change that start happening T-giving weekend up in Acadia). Same thing with the check engine light- it came on when the speedometer stopped working at first and randomly ever since and then once while the acceleration issue was happening. I have recently replaced the fan belt, the rear brakes, and the switch to my heater. I spent the past month in NH, so I did drive through lots of snow and ice and thus has to use 4wd high more than usual, but other than that it’s been business as usual. Though most of my trips are in the 2-5 hour range and the journey up to the North Kindgom (lovely New England) took 10 hours so maybe the increased distance had an impact… she’s driving around town fine now and not acting up for the mechanics, but I know the problem will emerge again as I make the 8 hour journey home to the Carolinas for Christmas and would love to get it fixed before then so I don’t have to hitch a ride with Santa (or triple-A).

I’d appreciate any advice you can offer.

Many thanks,

Acceleratorless in Bethesda

Wow! We seldom get such interesting posts. The only problem is, many of us don’t wish to wade through the flowery descriptions (nice, thank you) to get to the details. I think that’s why no one has responded yet.

Be that as it may. The most helpful information was nearly at the end of your post, under the heading “Other important information.”

Let me ask this; are you saying your Jeep drives fine around town and on low-to-moderate-speed roads, but has problems when you go on the highway and ask her to maintain a high cruising speed?

The fact that the Check Engine Light came on, or is on, is very important. Has anyone scanned your Jeep’s computer to see what the trouble codes indicate? If not, why not? You cannot ignore the CEL (well, you can, but it’s not a good idea).

At 180K miles just about anything is possible. You need to find out what’s up with the Check Engine Light. The results of a computer scan may be helpful.

Can you summarize your post?

You’ve had the car for a long time. Ever change the fuel filter?

It could be so many things, but backfiring points to raw fuel in the exhaust. Something as basic as a spark plug wire intermittently shorting or not conducting could do that.

rripstop’s guess at “fuel filter” is reasonable for low acceleration (been there!), except the problem would not come and go. From what I’ve learned here, speedometer acting up could be Vehicle Speed Sensor(VSS), whose failure could also cause some bad-running problems. But I think you have several problems, and you are going to need a good diagnostician.

Those two shops that “haven’t be able to reenact the failure” should have at least looked for stored codes from the Check Engine Light. If they did not, then I would not go back to them.

I know of several good shops between you and Wheaton, MD. I used to use Arman’s Checy Chase Service Center before he got burned out of his shop in Wheaton several years ago. Now he is on Connecticut Ave at Chevy Chase Lake. You might find somebody to your liking from the Car Talk Mechanix Files (hard to find from their home page; here’s the URL: http://www.cartalk.com/content/mechx/find.html ). I found Kensington Auto Clinic that way a couple of years ago. I have also used AutoServ (aka GTO’s or Good Time Ol’ Fashioned Service) on University Blvd in Wheaton. None of them is particulary low cost, but they all seemed competent.

Next time it happens, stop and open the gas cap. I think you will find it has quite a vacuum under it. It should run fine then. The problem is probably in the canister vapor recovery system and I think the code will show that. I’m also guessing that you tend to fill your gas tank to the top each time instead of stopping at the first click. You need to stop at the first click.

Negative vapor pressure with todays gasoline is almost impossible…Jeeps are morphadytes that are a collection of what ever parts were available for that particular production run… This vehicle obviously needs a mechanic with psychic abilities…But a fuel filter, a set of plugs, plug wires, distributor cap and rotor would be a good place to make a stand…

Have you heard of the ancient Chinese curse, “May you live in interesting times.”? It seems like you had some of that. Hope for, “Uneventful (of negative sorts)”.
“Backfiring” has two meanings. One is backfire through the intake of the engine. The other is, backfire through the exhaust. Which is it for your Jeep?
Could what happens to the engine be misfiring? With misfire, the Jeep would buck and jerk (without most of the sound effects). Does it do that?
When the check engine light comes on, and while it’s still on, go to an auto parts store and ask them to scan the Jeep’s engine computer. Many auto parts stores will do this for free, complimentarily, at no cost, and gratis. Bring those codes here for some erudite (hopefully) advice.

Cracking the gas cap open was a big help on my 83 corolla. Your intermittent problem may or may not turn out to be an old engine computer, and sometimes getting the codes read will tell you thet it is out of whack. Other times, you have to guess. Sometimes a bad oxygen sensor will leave you with no power and the car will slow down. Once the gas pedal is pushed enough, the power will surge right back. I don’t think the oxygen sensor is the problem. Your car is the right age for a computer to quit. Count me as one of the “I don’t knows”.

Runner–I want to try to clarify what Caddyman stated. While I agree that basic maintenance–which may have been ignored at some points in its 14 year/180k existence–is the best place to start resolving your problem, the Jeep is not a “morphadyte” (sic). I believe that the word that he meant to use was Hermaphrodite, meaning an organism having both masculine and feminine characteristics.

How About The Health And Well Being Of Your Buddy’s VSS?

Click this link and scroll down to [“page 3”]. Under “Keeping Up With Vehicle Speed Sensors”, read particularly “SYMPTOMS”.


Auto Zone sells this part for about $45. I’m not sure what a dealer gets. This should not at all be labor intensive to replace.

I would suggest having the wiring for the sensor checked out by a competent technician and see if she/he agrees that this could be the problem area before replacing the VSS.

Here’s what it looks like and where it lives. Click this link to Autozone auto parts:


Hi McParadise!

Sorry for the long description- the first mechanic I went to back here in Bethesda asked me to write everything down.

Yes, the jeep drives fine around town and on low-to-moderate speed roads- only had a problem once going under 60.

She’s at a jeep dealership now and I asked them to check the codes and they said the computer didn’t have anything stored on it code wise- I’m going to ask them to look again though at your suggestion.

Since they can’t get it to act up, they want to charge me a $130 bucks and give her back with no work done, but I know something is seriously going wrong in 5th gear on the interstate (particularly uphill and in higher winds- tougher conditions)… but downshifting doesn’t help when things go wrong so I’m guessing it’s not a matter of the gears, but of something getting heated up???

Yes. My jeep is acting up on the interstate at speeds around 60 mph… she can run along at that speed just fine for 200 miles or 70 miles or 10 miles and then all of sudden, it’s like the engine is suffocating (lack of air or fuel) and it starts chocking up, failing to maintain acceleration, I don’t hear much from the engine, but can feel it struggling and downshifting doesn’t help… it also backfires from the back exhaust pipe when it has this problem and the speedometer sometimes goes out. However, the CEL has only come on once while this was going on and by the time I got somewhere it was off.

Good suggestion- I will check into that- can’t recall off the top of my head.


I am backfiring through the exhaust. But the engine feels like to me that it’s suffocating- having intake problems… I thought it was an air intake problem with the high winds and large hills, interstate speeds… but it could be a fuel intake problem.

The engine just seems to go haywire- not so much bucking and jerking- as like it’s lost its place… can’t find what it needs… fuel, air, a gear… it’s hard to describe…

Good suggestion about the CEL as it looks like I’m stuck until it starts acting up again!

That article on the VSS (Vehicle Speed Sensor) is one of the most excellectest ones I have read. I recommend it to knowledge seekers, and the like. Now, that link is in my Bookmarks.

wow, that symptom list does sound like exactly what has been happening to my jeep and my tires are several sizes larger than the original ones that came on the jeep. My speedometer has been wacky and I noticed I was burning a lot more fuel on my return trip to DC than my trip up to NH the month before…

Thank you for the suggestion- I’m going to look into that straight away!

Yes, thank you for that link, CSA! I learned quite a bit of new information from that link, and you never know when that will useful.

Different strokes for different folks. The interesting details made me want to keep reading every detail here. Alas, I had no idea at all what the problem was, but I enjoyed the detail.