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!
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.