I bought my G at 66k miles in May of 2009. Now as of February 2013 I have 135k on my G and have in total changed (5) coils due to them blowing on me. I have never had the spark plugs replaced since I've had the car. Usually Id just have the coil changed when they blew to get it back on the road. My gas mileage has decreased and I'm only getting about 120 a half tank when I usually average about 160-180 per half tank (usually running 60 mph highway on average). I keep my oil changed religiously and fluids checked. I'm not a "hands on" mechanic with my car. I just want to keep her in good running strength. Does anyone thing having all the spark plugs changed would give it a boost? It seems to be a little sluggish also..not booming with power as I remember her. Also, what is a roundabout cost to have them changed if I was to purchase the sparks myself? I can get them at cost.

Also, suggestions on what name brand spark plugs to replace my stocks with?

All suggestions would be appreciated.

Thanks!

-Traci

 

I have 168k on my car and have never had a coil pack go out. I find it odd that you gave had 5 go out.

Plugs are supposed to go 100k so, if you've never changed them, they are past due. Stock are ngk platinum, but some like me go with ngk iridium. Platinum will will go longer between changes, but iridiums are pretty close and are more affordable. I would stick with ngk as other cheaper plugs don't last long or don't work right. As for cost, I would guess the book is 2-3 hours labor. At about $65 an hour you are looking at $130-$195 for labor alone, but just a guess.

 

Thanks for the advice! Yes, I had 5 coils go out in literally 6 months time. All at once. It was week after week I was blowing the. Havent had any trouble in about a year. I will look into the new plugs. I think it will do the car a lot of good.

 

I'm at 120K, still on original COP's. Kindo odd that you've been through 5.

But yes, you are overdue on plug changes. I did mine at 110K miles and gained about 1 MPG. Coworker went 225K miles before he started getting misfire codes on his original plugs. Thats an extreme example though.

I replaced with stock NGK plugs. Took me an hour to do all 6 myself. If paying something, they will probably charge you 2-3 hoursI would assume.

 

Thanks alot. The coils blew one after the other. Before coil problems I had a complete shut down on my car and the shop said they had to replace my wiring harness. After that it was down hill. 5 blown coils, leaking rack and pinion (replaced), replaced rear wheel bearings twice due to the first ones going bad (warranty on parts covered), and now its slugging going from 40mph-50. Maybe its nothing bad. I take meticulus car of my g, maybe it was just a weird case.

 

Have you changed your AT fluid lately?

I only say that because lugging at 40MPH is a common complaint with the AT

 

Had it completly flushed out and cleaned out a year ago. I had the shop look at all my fluids a few months ago when I was getting new brakes and wheel bearings. Said everything looked good. Do you think running some sea foam through the ole gal may unclog her a bit?

 

When plugs are changed, check them for even color. You may have partially clogged injector(s).

Run some quality fuel injector cleaner such as Lucas and see if mileage improves.

 

For fuel system cleaner, redline and gumout regane are some of the best.