Help 90 Q45 Engine shaking, Idling and Driving very rough

[my_dog_wolf]

Hey all, I bought a 90 q45 that has sat for 2 years. At first it would not start. I chaged all the fluids, new fuel filter,spark plugs,core packs, MAF sensor, and seafoam in the tank. The car runs now but it runs very rough and at idle. It dies when it comes to a complete stop. The engine shakes really bad around 2000 rpms, but smoothes out after that. There is no CEL.

I am not a mechanic by any means but I have had 7 Q45's. So I have gotten to know a little something about this car. LOL.

Please help me. You guys have helped me learn through the foruom.

[qship96]

7 q45's.......did the last 6 die of mechanical problems? Correctly maintained, each Q should have had a 250-300,000 mile lifespan- what went wrong, over and over????

[goody90q45]

The first thing I would suspect is bad fuel injectors. My last 90Q had a junkyard fuel rail put in that ended up with 7 injectors that ohmed good yet two of them were plugged from sitting so long. I'm sure you've ohmed them and would have mentioned if any were dead. If you suspect plugged injectors maybe add 2 bottles of Redline inector cleaner to the gas tank and see if it cleans them up.

[my_dog_wolf]

Nothing went wrong with the cars. Just buy and sell or just lose them( long story). I just sold a 90 Q45 last week. I am just going to retore the (0 that I have and then get a 94-96 and a 99-01 to complete my mission.

[jimbyjimb]

You have either a cylinder miss or cylinder misses more than likely. Probably, as suggested, it is a fuel injector or injectors. Ohming diagnoses any electrical problem but mechanical issues are another problem. Do as stated with Redline but also Ohm injectors and see whats up. Could also be bad coils, wiring, spark plugs, etc... Most likely injector with G50. If all 8 ohm ok and the redline doesn't help I suggest a visual inspection of spark plugs and making sure the coils are still good before tearing in on an injector job.

[maxnix]

Think he is in an ethanol area, so ohm test injectors first!