94 Infiniti Q45 (Check Engine Light off/on, engine dies)

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Apollyon67
Posts: 3
Joined: Wed Sep 10, 2014 12:44 pm
Car: 1994 Infiniti Q45

Post

I've searched the forums for a while now looking for a solution to my problem, unfortunately I haven't found one yet. Nor have I found a problem that matched mine.

A couple months back I bought a 1994 Infiniti Q45 with 125k miles on it. For the price, the desperate need for a car, and the fact that the owner was a family friend, I made the choice to purchase.

A couple weeks into owning the vehicle we had to replace the radiator, water pump, and the clutch fan. The mechanic looked the car over and determined that the problem had been solved. Recently however, the engine has formed a very rough idle (You physically shake in your seat and if outside of the vehicle, you can see it rocking back and forth.) It's also thrown the check engine light but it doesn't last long. When the light comes on the vehicles RPM's will NOT go over 2k rpm. The car will die whether you're stopped or driving 65mph down the freeway.

Since those problems started up, we've replaced the fuel pump and fuel filter, we've also ran sea foam in it and only use premium fuel... But nothing has worked! :mad: I'm at a loss as to what it could be or even how to troubleshoot this car. I feel like this car was built so that any work needed would have to be done with the manufacturer.

Anyways, I'd just like some ideas as to what it might be. I'm not the most experienced when it comes to cars, however it appears that owning this car might turn me into a mechanic. Lol.

I've read that it could be spark plugs, injectors, MAF, etc.

Current problem
-Very rough idle
-Car jerks very hard when the engine decides to act up
-Check Engine comes on only for a few moments at a time
-RPMs seem to cut off at 2k (Almost like I'm redlining the car)
-Engine dies anywhere from 1-10 times within a mile and a half

Work done on car
-Fuel Filter and Pump
-Sea Foam
-Radiator
-Clutch Fan
-Water pump

I'm willing to try just about anything as long as the possibilities of it working are high. I'm at a loss. My next immediate step is to try reading the codes, but until then I think it's a good idea to ask for some assistance from this wonderful community.


3Q Jay
Posts: 2545
Joined: Sat May 08, 2004 6:23 pm
Car: 94 Q45a
95 Q45a (sold)
97 Q45t (sold)
01 B15 Sentra (Daughter's)
Also Mine...
2010 A6 Avant
1977 F-150 (460!)
Location: Florida Coast

Post

have you measured the fuel pressure at the rail?
read the code(s) OBD-1 not too perceptive, but it is a place to start.
home run guess at this point is MAF, but that is a guess based on symptoms
invest in a consult-1 like interface to your laptop if you want to get serious and minimise shop time.

Apollyon67
Posts: 3
Joined: Wed Sep 10, 2014 12:44 pm
Car: 1994 Infiniti Q45

Post

I haven't measured yet. I just tried pulling the codes and got a 55(system okay). The light comes on and off while driving and I guess it's not storing whatever code is being given. I keep hearing it might be the MAF, so I guess the next move would be to start looking into that. Hoping that's what it is! :gotme

OwnerCS
Posts: 1771
Joined: Thu May 27, 2010 4:34 am

Post

Where are you located? It would be great if you could get a NissanDataScan reading on the car while it is throwing codes.

Apollyon67
Posts: 3
Joined: Wed Sep 10, 2014 12:44 pm
Car: 1994 Infiniti Q45

Post

OwnerCS wrote:Where are you located? It would be great if you could get a NissanDataScan reading on the car while it is throwing codes.
orlando, Fl. Specifically the Windermere area.


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