Nissan Repair: 1994 nissan maxima, rich fuel mixture, nissan maxima

Question
Calvin, I have had this vehicle about 2 years. Bought it cheap and added a water pump knowing it needed it going into purchase. Had been running well with little things wrong that I knew about when I purchased it such as rear speakers didn't work, seat belt light/bell comes on periodically, rear power window short? works after a minute or 2. 150k miles on it when I purchased it for $750. I can deal with these things in exchange for the good mileage it still gets 23/33 and has always passed testing for tag renewal. Within the last year, tachometer broke but speedometer still works so still no problem. This week, however, I started it and after 5 seconds it immediately went into a rough idle and sounds like it is preparing to die but doesn't. Loss of power but still drives ok. Simultaneously with rough idle, check engine light went on. Took to shop and hooked up Genysis machine but it couldn't get a signal to get a code for problem solving. I have never run out of gas but do routinely run down close to empty after fill-up to top of gas cap each 2 weeks. I dont have much invested in car so am unsure if I want to put much into it unless I am confident it will fix problem. Is there a cheap way to inspect it without committing to purchase and paying $$$ just to find it is too expensive to repair. I can drive it til it dies but want to squeaze everything out I can since I have no monthly car payment. Not sure what this car is worth, but it is probably worth more to me than it's market value, at least prior to this weekend... Thanks, Jeff

Answer
Hi Jeff -

Couple quick checks -

Pull out each spark plug one by one and check the condition. If one is wet or fouled, then replace it. Next thiing you check is the distributor cap and rotor. there might be some carbon tracking there.

If the plug electrodes are black - you might be running a rich fuel mixture. Check all vacuum lines to see if you have a vacuum leak. Easiest way to do this is to get carb cleaner and spray it lightly all over the engine slowly. When the idle improves, you have found your leak.

Try these tests, and get back to me. If you still have not found it, we can go to the next step of diagnosis.

Hope this helps -
aloha
calvin