1993 Altima runs like a lawnmower

First my confession: My sister sold me this car about 5 years ago for a song as a hand-me-down. Ever since I’ve had it, it has run (especially under 15 mph) like a lawnmower or an idling Harley. Since I wasn’t in a position to deal with it at first, I let it go for awhile and nothing ever happened, so I gave it to my college son for his transpo. and it just kept running and running (for over 50,000 miles now) with nary a break down or glitch.
It’s now started running so rough it cuts out if you don’t keep your foot on the gas, so I guess my luck is running out.
Before she sold it to me, a mechanic had told my sister it needed a timing chain. He quoted her 1600 bucks so of course I blew that off. I also discovered that theses timing chains are supposedly designed for the life of the car.
Another thing that is happening is, when it’s running there are two fuel injector electrical connectors that I can disconnect without any affect whasoever on the idle. If I disconnect either of the other two, it dies immediately.
So, could I have had bad fuel injectors all this time, and could they cause the motor to idle like a Harley? Or is it more likely that it is indeed a bad timing chain(s)?

Chains are supposed to last for the life of the car but timing can ‘jump’ where the car starts running like crap. That could be caused by a defective chain but more often than not, a car will not run for that long with it because it will likely jump again - eventually to the point where the timing is way off and it won’t run anymore.
Have you have the car’s timing checked? That would show whether the timing ‘jumped’.

That being a four cylinder car, you definitely need four injectors to have it run normally. Since you’re clearly capable of identifying the injector connector, perhaps get a multimeter and measure the resistance of each injector’s coil to see if some have opened up. If the ‘bad’ ones measure totally differently than the ‘good’ ones, you’ve bought yourself a clue as to where to look next.
It could also be that two have totally clogged up or are defective in some other way. You could pop them out and see if they spray when you’re starting the car.
You could have had a near clogged injector and it just got progressively worse over time.

If I read this right between the lines, this car basically hasn’t been cared for at all. An occasional oil change perhaps and not much more? E.g. how old are the spark plugs? wires? filters?

There’s not much point in doing a whole lot until you just do basic maintenance.

The fuel injector thing could point to the fuel injector - or it could point to any number of other things wrong with those cylinders such as plugs, wires, or compression.

One early 90s Altima engine was infamous for its rattling timing chain that often destroyed the timing cover and oil pump when drivers ignored the rattle at idle until catastrophic failure. 15 years ago the entire parts package to repair those engines was $400 after all installer discounts. And of course, when the chain failed valves could get bent.

Great info so far. Thanks.
As far as basic maintenance, I have to smog it every 2 years (which it’s passed 3 times) and each time it gets new plugs, air filter, cap and rotor. I’ll check the wires though as I don’t think I’ve changed those. I will also follow RemcoW’s suggestions.
Thanks again.

OMG…you mean you guys have been running this vehicle on 2ish cylinders for over 50 THOUSAND MILES? Ugh… Something is amiss…bec if you have 2 dead cylinders then it would NEVER pass any smog test unless…it wasn’t spraying fuel into the dead cylinders? Even then passing that test is a bit iffy. Hmmmm Jeez… You need to figure out whats up with those 2 cylinders… It does sound as though they might not be getting fuel… You would have to pull the spark plugs after running it for maybe a few min…see if they are wet with fuel…if not, you something is off with the injectors for sure and the fix is likely there…IF they are wet…then you need a compression test to find out the health of those 2 cylinders… My God…I couldn’t imagine driving 5 blocks with an engine in that state of neglect…High threshold for severely annoying things, poor fuel economy and painfully slow vehicles I presume? You have some tests to do…let us know.


How well does it cut ?

Getting and relying on advice from the good folks here after such a dismal history of neglect is (IMO) almost worthless. You have admitted basically ignoring any and all types of basic care for this vehicle and driving it regardless of condition for well over 50k. The problems you have could be anything . . . from timing chain stretch through bad ignition wires . . . on a 19 year-old vehicle! My suggestion is that you start with a basic check of the engine and vehicle overall . . . for your safety and ours . . . and then a tune-up and diagnosis of your problems. Any mechanic could run the basic tests in an hour or so and do a simple tune-up in another hour. From what I can see you’re way ahead on car-care costs anyway. After that you can address individual problems and possible solutions here (or anywhere) with a better possibility of success. The posters here are pretty smart but I think that you’re looking for a free on-line miracle cure for your admittedly horribly cared for 19 year-old car. The posters may hit a homer but I think you would be better off doing things a bit more logically and starting at an engine assessment and tune-up as I suggested. Good luck! Rocketman

Yes rocketman. It sounds like a basket case.I would think that most shops would avoid such a nightmare.My solution to avoiding such problems was demanding more than the cars value as a deposit against the repairs.

Kinda scares me to think of the brakes, suspension, steering, and other safety items the OP might also have ignored. It just plain amazes me how few fatal accidents there are on the highways knowing stuff like this occurs and seeing how some folks drive. I worked at a truck stop at the intersection of two major highways in the midwest while I was in graduate school and it just plain floored me as to some of the stuff I saw coming off the interstates. I guess you guys have similar experiences. Hopefully the OP will get this stuff checked as well as the engine issues so he’ll be around to post here in the future. Rocketman

The engine on my father’s Corvair sounded like a lawn mower. It was made by briggs&Stratin.

“The engine on my father’s Corvair sounded like a lawn mower. It was made by briggs&Stratin”. That’s interesting. The Briggs & Stratton on my lawnmower sounds like the engine on a Nissan Altima.

Lawn mower, generator and other small motors may sound a little rough, but at least you can hand crank them in sub freezing weather. One of The next best makers of small quiet 4 stroke motors is Yamaha IMO. Yamaha generator and 2.5 canoe kicker are the best I’ve had in that respect.

Sorry to give the impression that I did absolutely nothing to this car. I’ve been replacing brakes, belts, tune up parts, wheel bearings, cv joints, and other easy stuff on a multitude of cars I’ve owned for over 30 years. I replaced the brakes when I got this car and once since, the tires when I got the car and once since, and the cv/half axles. So, while I may neglect a motor problem rather than nearly remove and disassemble it on a car worth lees than 1000.00, and this may leave me on the side of the road calling AAA, no one’s safety is being compromised.

The timing was nearly spot on when I checked it (thanks RemcoW), so the Nissan dealer mechanic who told my sister she needed to replace the timing chain was apparently mistaken. I’ve replaced 2 suspect fuel injectors, and the jumpy idle has smoothed out so much that I think that was probably the problem all along.