Absolute best spark plugs for '04 Grand Cherokee Laredo....
Hi there, I've been out of here for awhile so I apologize if this is a redundant post....
Well its about that time I'm almost at 60K, so I'm gonna go ahead and do this before I go on vacation in April. I recently purchased a camper so I want to squeeze every little bit of power and efficiency out of my beast. I've heard positive things about Bosch Platinum +4s' - like they put out the best "bang" - to negative like they're junk and the tips break off into the cylinder. I've heard of Iridiums, but don't know much about them.
So I'll ask all you car peeps, what would be your choice for spark plugs? Cost isn't an issue since its only done once every great while. As far as the other stuff I use, I use Mobil 1 full synthetic oil and K&N air and oil filters.
Also do changing to high end spark-plug wires make any difference? Thanks for any help you can give me...
i tried the bosch +4 thingys, they made my jeep run like a 3 legged dog on acid..
brand new set of champion copper cores are the best from what i've heard, BUT i've also been hearing about NGK plugs lately and that they're supposed to be very nice to jeep engines as well. i bought a set of NGK's from autozone about a week ago but i'm still waiting for the damn heep to come back from the dealer (grenaded rear end) to give them a try.
04 WJ 4.0
6.5" IRO Front and Rear Longarms
Soft 8's, 285/75/16 BFG Mall Terrains
Super 44 with 3" Side Dump
Dana 44a, 4.56's
Q: How much of a performance improvement can I expect from changing plugs?
A: A common misconception is that changing spark plugs will result in a large power increase. In most cases, removing even seriously worn out spark plugs will only result in very modest power gains, typically about 1-2% of total engine output. This could be even less for computer-controlled vehicles, primarily because most newer vehicles have more powerful ignition systems and the vehicle's computer can make adjustments so that vehicle operation seems smoother and more seamless.
Many people think that simply supplying more spark to the firing tip can and will combust more fuel. What they don't understand is that most newer cars' engines are so efficient that they are already burning all of the available fuel. Simply adding more spark voltage can't burn more fuel because there is no more fuel to burn.
When a stock or near-stock engine is given a fresh set of spark plugs, peak efficiency is restored. The power gains that come from this restored state of tune are usually minimal. Any company that tells you that their spark plug will provide significant gains in power in a stock or near-stock engine is making blanket statements that may not be supportable.
As others have said, the best and recommended plug for the 4.0 is the cheap base model copper cores. The 4.0L does not benefit from the high end "fancy" plugs. And in some cases the more expensive plugs make 4.0s run like crap.
BTW, your WJ does not use plug wires. They use a distributor less system with a coil pack rail over the plugs.