Ok i need help. Bad. Here is the problem. 2002 xkr. 88,000 miles. After hard acceleration, SOMETIMES when i get to idle it runs rough. Sometimes dies. If i stay on it like getting on freeway then hitting the cruise, no problems. Never rough if I don't drive it like i stole it. Never rough under any acceleration. Only if I get on it hard then get right off. Ok now for what i done.
New fuel pumps
new fuel filter
new plugs
new coil packs. All of them
new exhaust. Cat back
removed cats
found no air leaks. Vacuum or otherwise
doesnt throw a code
if i just putz around in it it never happens
all work that i done was one at a time with the same results each time. Took it to jag after about 1/2 of the changes and they said coil packs. They replaced 2. 180 miles home and it still did it. I've been chasing this for a few years now.

 

My guess, leaking, dripping injectors. Wide open throttle then quickly off throttle might mean one or more injectors start to drip rather than spray. Have them cleaned before replacement.

 

Thanks how do i clean them and can a test be done to buzz check individually or just clean them all

 

Specialist job and if they're faulty it's mechanical so no way for you to test them.

 

If they are clogged or dirty, you can remove them from the car and let them soak in CLR for a while, followed by a few rounds in an ultrasonic jewelry cleaner, if you've got one. Let them dry thoroughly, then replace the basket filters and o-rings.

 

cool thanks. I have an ultrasonic parts cleaner so I will use that and buy a rebuild kit for $70. trying to get around 8 new injectors

 

When you get off the gas does the idle immediately go back to normal or does it hunt around as if trying to figure out what to do and take a few moments to stabilize? If so you may have an undiscovered air leak in the TB or failing throttle motor. This quote makes me wonder..."SOMETIMES when i get to idle it runs rough. Sometimes dies." Really typical of an air leak in or around a carb or TB. Does it happen at all when you just rev the motor and suddenly get off the gas?

There are available injector cleaning kits that use a pressurized cleaner to do individual injectors.


I'm not aware of any rebuild "kits" for injectors on the market and certainly not ones that could flow test and match them.


There are a couple of U.S. based businesses on eBay that offer a set of 4 or 8 remanufactured/rebuilt injectors with 5 to 10 year warranties for as low as $125 for all 8 so check there as well.

 

The "rebuild kits" usually are just new basket filters and o-rings. I've used a kit off ebay for the 4.2 engine. Costs around $30. Of course, if there's something wrong internally with the injectors a rebuild kit won't fix it.

 

it only happens when I'm in drive and go to wot then let off after say 1/8 mile or less. then as I'm slowing and the idle comes down in a normal fashon, sometimes.... it will idle rough. lie 50% of the time. if I hold it wot to say 120 and keep it there or come back down to anything but idle it never does it. just to sit there in park and rev and let off never affects anything.

 

good info thank you