Bimmerdude

My fiance has a 1997 maxima with just under 150k on the clock (V6 auto).

Today it threw the check engine light (Cylinder 1 misfire) and began "bucking" very badly under moderate loads and relatively low engine speeds (really bad in the 1300-1700 rpm range, and at idle) and I discovered there was already a stored code for knock sensor.

I replaced the knock sensor, not expecting it to change anything, and it didn't, but when test driving the car after I found that the problem only occurred once the car was up to temp (10 minutes or so in).

I then pulled cylinder #1 and #3 plugs to inspect, they looked aweful and I will be replacing those soon.



Right is #1, left is #3. The color difference was less dramatic in person.

I noticed there was oil in both wells, and it smelled significantly stronger in #1. Put the plugs back in where they came from, but swapped the coil packs.

Test drove the car for 20 minutes - ran the best its run in two years. She commutes to law school 50 miles each way 5 days a week, I need to figure out if I did anything to fix the car before it starts stalling.

Feels how my turbo car did when I had bad spark blowout - almost like it just completely stops firing for a moment - and I'm not really convinced I've actually fixed the problem by swapping coil packs.

Any ideas? I don't have a scan tool that shows 02 sensor values or MAF etc., but am game for other suggestions on how to check those items?

Dylan Drift-King Murphy

To check the MAF all you have to do is unplug it while it is running. If unplugging it DOESNT do anything, than the MAF is bad; but if it DOES, it is good.
As for the the rest, My advise is to change both Valve Cover Gaskets(Make sure to get the set with the Spark Plug Tube Seals, The full set is about $54.00 at O'reillys and Advance Auto Parts.), Change the Intake Manifold Gaskets(About $15.99 at O'reillys and Advance Auto Parts), Change the Oil/Oil-Filter, and Change the Spark Plugs(Your best bet is to get the NGK Iridium or the Bosch Platinum Iridium 4 spark plugs.) And maybe Try completely FILLING your tank with 89 octane and than using NOS Octane Booster. You can get it at Walmart for about $10.00 and it works AMAZING, I use it in my car about once a month.... Oh and only use about 1/2 the bottle per full tank. Its powerful stuff.

i8acobra

Looking at those plugs... it's time for new ones. Try that first. Also, not sure if your year has replaceable spark plug tube seals or not. If not, you'll need a new valve cover. Either way, replace those and obviously the valve cover gasket.