Thread: Car getting horrible MPG

Originally Posted by Mercenary

Update

I had it scanned today and it was misfiring in most of the cylinders (5 out of 6) but only when it was revved (not at idle). They pulled a plug said it looked like the fuel injectors were somewhat clogged. The shop suggested that I have them do a fuel injector service on it (costing $140). They also told me not to run copper plugs (I use Autolite coppers one range cooler than stock) in the GTP only platinum, saying that they are probably playing a part in why I'm having issues.

Any thoughts?

Well, if it's misfiring because of the coils then your plugs will foul anyway. I'm the kind of person that believes if the 5-6 coils are not firing properly, then how far behind is the other going to be from failing. If you can afford it, replace them all, put in some new plugs, dump in the injector cleaner and see if that helps, and do the Seafoam in the tank and in the air intake just to make sure all the stuff up top is nice and clean.
My 2 cents.

Originally Posted by BANDIT

Well, if it's misfiring because of the coils then your plugs will foul anyway. I'm the kind of person that believes if the 5-6 coils are not firing properly, then how far behind is the other going to be from failing. If you can afford it, replace them all, put in some new plugs, dump in the injector cleaner and see if that helps, and do the Seafoam in the tank and in the air intake just to make sure all the stuff up top is nice and clean.
My 2 cents.

I already replaced the coils a couple of months ago and I just got done running seafoam in the gas tank. I think you might of misunderstood me when I said 5-6 cyclinders were misfiring. I didn't mean # 5 and # 6 were I meant #1, 2, 4, 5 , and 6 all were misfiring (some more than others tho).

@Silverstreak

I've never had the pressure checked but I'm gonna replace the fuel filter today and do my own treatment on it. Funny thing is my driver's side window won't go up now so that's something else I gotta play with. So today is car day (gonna change the oil, coolant fluid flush, and whatever else I can think of).

I'm thinking about just getting stock coppers just to see what will happen. I don't really understand why platinum would help because everything I've read on here always suggested copper (platinum is for people who don't like changing plugs). I'll be checking the thread through out the day for any advice and I'll update the thread tonight with the results.