94' Q45t running rough with 'Malfunction Indicator Light" on

[nadirgholi]

I went over a piece metal object on freeway which hit the bottom of the car really hart. Pulled over, looked under the car to make sure no visible damage done to oil pan, etc. Everything looked good. I drove the car for about 10 miles or so there and stopped by neighborhood Costco for some shopping. After 30 minutes there I returned to the car and started it. It was running like crap with "Malfunction Indicator Light" illuminated. Looked under the car. Everything looked normal. The next day I took it to local Infiniti dealership. They put it on the rack and checked everything under the car. They said no damage. They connected the Consult to it and said the reason for running rough is that injector #1 was bad. They replaced injector #1. It was running fine for about three weeks before the same exact symptoms returned. I took it in again. They said it is inject #5 now. A piece of metal on freeway hit the bottom of the car and the immediate impact is bad injectors. It bits me. Coincident or whatever it just puts me at unease what to do next. Change the remaining 7 original injectors or is it something else totally unrelated to injectors. The car has 225000 miles. I replaced all the hoses including the ones under the plenum about 60000 miles ago not to mention I have been using the best fuel, synthetic lubricants, and coolant. The car looks very clean in and out. Any advice out there about likelihood of something else other than injectors causing the “Malfunction Indicator Light” stays one and running rough?

[Q45tech]

Are you using Ethanolized gasoline or do you drive 100 miles out to the interior each fill up to get conventional gasoline?

Review the sudden rash of very recent injector failures in Texas from ethanol.

However in any case 225,000 miles is very good life for injectors.

[maxnix]

I think Plano is in the DFW metro fuel blend area, so if you don't go north to get non-ethanolized gasoline, better add a can of ISO-HEET to every tank.

[nadirgholi]

Yes. Ethanol (10%) became main stream fuel in DFW area some times in 2006. It makes all sense now.

So I am in no win situation even if I replace all injectors because the fuel here is 10% ethanol any way and it wouldn't take long before the new injectors start failing.

I did start adding two bottles of Tekron to full tank of fuel. It helped the first time, but not any more. Is ISO-HEET totally different and more effective than Tekron?

[maxnix]

Is ISO-HEET totally different and more effective than Tekron?

For water contamination of fuel, yes. Techron doesn't dissolve water, it is a detergent for fuel system. But it is not as strong as BG44K.

[96Qowner]

So I am in no win situation even if I replace all injectors because the fuel here is 10% ethanol any way and it wouldn't take long before the new injectors start failing.

Not necessarily.

The real issue is WHY are the windings failing? I suspect the ETHANOL in gasoline today is attacking the potting compound of the injector body, causing it to swell and pull the wires in two internally.That's the 'post mortem' I did on 3 'original' ones off my '94--all wentprogressively HI ohms in 3 months of ethanol in gas. The other 5 had been replaced by P.O. just B4 I bought it 4 yrs/50K miles ago and have different potting compound.

zer...09350

So, apparently newer injectors aren't vulnerable to attack by ethanol.