My 1991 Maxima has a problem I cannot solve. It runs great most of the time. Then when I am driving either on the freeway or residential the engine will start loading up with excess fuel and cutting out. When it does cut out I lose most of the power and am forced to pull over. If I stop the engine for about an hour I can start it up again and it will run good. I have taken it to a mechnic and he has checked out all of the codes. Nothing!! The problem is beginning to get worse. It has happened three times in the last two weeks. Anyone got a clue as to what the problem might be or how I can find out? I am frustrated and can't drive my Maxima more than five miles away from home for fear I will break down. jwd1@humboldt1.com

 

I had a somewhat similiar problem with my 90 SE .. it started as a stumble/hesitation on takeoff from a stop, then began cutting out the highway, it would always start right back up and run as strong as ever, then it got progressively worse, it would cut out and would not start for longer and longer periods.. the ECU showed 55 totally normal .. two different nissan dealerships could not diagnose the problem.. one day, quite by accident, with the hood open and the engine idling.. I am leaning on the driver side fender and drumming my fingers on the black fuse/relay box inside the engine compartment.. and the car dies .. I start the car and rap on the fuse/relay box and the car dies again .. inside the fuse/relay box was the relay that supplied power to the ECU .. I replaced the relay and the problem never came back.. about $20 at the local nissan dealer .. this could be your problem.. Dave

 

The symptons you described are very familiar to Mazda owners. I have heard this from many Mazda owners (I had one several years ago) It would die without any reason specially on the highway forcing me to pull over and then after a short while it would start again. The local Mazda dealer fixed it by replacing ignition module (inside the distributer) He explained that after the car warms up fully, the faulty ignition module cuts the current off. The car starts fine after it cools down. I would check what Dave said and if that is not the problem check your ignition module

MSK 90SE

 

Fuel pump.. check it out.

 

If the above suggestions don't work, I'd also check the fuel pressure regulator.

 

Mine did that just the first time (after sitting overnight) when I gave it gas, then it never did it again until it sat again. Two things solved this: 1. New front engine mount. 2. New fuel injectoer (all 6).

 

..In order to eliminate most of the possible causes of this problem check the ECU for a error code.. this is what the nissan techs do when they "diagnose the problem" .. that's a $65 hit each and every time .. every sensor in the engine
is polled by the ECU and responds to the ECU on a real time
basis continuously.. when the ECU gets an incorrect response from one or more sensors it identifies that sensor
with a diagnostic error code which is stored in the ECU.. this is what the nissan techs look for..
The reason I could not find a error code in my case became very obvious after I stumbled on to the cause.. the relay that was faulty in my case was the relay supplying the +12v
to the ECU.. and the ECU would reset itself after power was
restored.. so that when I did a diagnostic on the ECU it always came back with "55" which is a no fault detected error code ...
These relays don't last forever and the maxima has a bunch of them.. my relay began acting up after 8 years and only cost $20 or thereabouts to replace .. disconnect the battery
first as a precaution
Dave.

 

The problem still exists(see message below). I did take your suggestions and made the inquiries. Didn't find any solutions, but I sure appreciated your ideas. Moisture seems to be a key variable. Whenever it is raining or the streets are very wet the problem happens. I have checked all of the connections, air blew all of the places I thought might have been wet and jiggled more wires than I can count. Nothing! The engine seems to be loading up with fuel like the choke is on. My thought is that for some reason unknown the engine heat sensor maybe be mis-sending a message to the computer that the engine is cold therefore sending extra fuel. Can't imagine what else would send extra fuel. Again, I do appreciate your help. Thanks, jwd

 

It sounds strange but imagine what happens to the catalytic
converter when it is suddenly get cold from a road water. Its working temperature is very-very high, and when the water quenches it the passages in the cells got too narrow?
Sounds silly, but ...
DDD

 

Give this a try .. disconnect and plug the vacuum hose to the EGR valve .. there may be two vacuum hoses .. isolate the valve.. see if the trouble returns..
dave.

 

Problem probably long solved and my comments might not fix the nissan at all...but can't hurt a thing to post. My Jeep did the same thing, wrestled with it for months...never knew when it would leave me stranded..only to start beautifully 30 minutes later. The ex did many things trying to fix...first tuneup ever..at 110K, new plugs, wires, dist cap, new fuel filter, etc. Finally took it to dealer..was the ignition relay switch.

 

Thanks for your reply. I found that the air flow sensor was the culprit. I live near the ocean and with the salt air the sensor corrided on the inside and we could not see it. Looked great from the outside. After more money than I could afford my mechnic finally found the problem. My baby has been running great since.

Again thanks for the response. Everyone was really helpful. JWD