Injector?..Coil?..help

[silverhawk]

So I'm on a trip across state yesterday and everything is fine until out of nowhere I through a check engine light and power, not turn off just loss of power. She bucks when I try to accelerate anywhere under 3500 RPM. At idle it feels like a miss (has a real noticeable vibration.) This has been going on for about 400 miles and every so often it will run normal for a max of 20 miles and then go back to acting up. It also has been fine when I first start the car but once I get going it starts the bucking again.

I was thinking a coil went bad but then that doesn't explain how it works OK sometimes. Maybe it is just going bad? or an injector slowly seizing?

Any thoughts would be greatly appreciated. Thanks in advance.

matt

[silverhawk]

bump....anybody have an idea?

[atdM3]

If you have a code reader, you can determine what fault you are having. If not, go to Autozone and they will pull your codes and will determine if you have a misfire. The code will tell you what cylinder is yielding the misfire.
My experience is that the actual rubberboots that attach the coil go the plug go bad. The rubber gets brittle and you do not make good connection to the plug.

[art@rmeuropean]

Start out by pulling the codes.

[Vonbimmer]

+1 for pulling the codes. My guess once you have the codes is MAF, but be sure to pull the codes.

[LuxoM3]

FWIW - given the age of the car and the symptoms... I can't say coil totally ... but it sounds like it.

Fuel issues don't do that unless your pump is dying... but fuel pumps just tend to die on our cars.

So next bet is spark... and coil is the most common.

[oasay07808]

I had the same problem. Pulled codes and got a misfire in one of the cylinders. Plugs were recently replaced so tested and turned out to be a bad coil.

[Roguls]

FWIW - given the age of the car and the symptoms... I can't say coil totally ... but it sounds like it.

Fuel issues don't do that unless your pump is dying... but fuel pumps just tend to die on our cars.

So next bet is spark... and coil is the most common.

+1.

Update us when it's fixed.

[nozatechm3]

I had a same problem till when I fount out the rubberboots cracked and it caused weak firing...

Code reading would be first but just check it first.

[silverhawk]

I haven't had a chance to check the codes yet, crazy work schedual....

I checked the coil resistance last night and they all read right at 0.2 ohms. Bentley says they should be 0.4-0.8. Does a bad coil read less or more resistance anyone know??

[thejlevie]

The first step is to have the codes read. If the codes only report misfires there are two general cases. One case is misfires on particular cylinders and the other is general misfires. Misfires on one or two cylinders is probably cylinder related, but general misfires or misfires on many cylinders is probably an A/F ratio problem common to all cylinders.

If the codes indicate the first case the first action should be to pull and examine the plugs on those cylinders. If there's oil in the plug well, the coil boot is in poor condition, or the plug is in poor condition you've probably found the cause of the misfire. If not, swap that coil to a different cylinder, the plug to another, clear the codes and see where the fault moves.

If the codes point to the second case, the first action would be to look for intake leaks. After that, there's the possibility of a bad MAF, aged pre-cat O2 sensors, flaky CPS, fuel delivery problem, etc.

[giterdone]

I know I always bring this problem up, but it also sounds like a Cam Shaft Position Sensor. Your car will still start, just runs rough, and under 4000 rpm it seems like you are missing a cylinder or two. At times it would run fine, but then it would go back to being sluggish.