krmaxima

iTrader: (13)

My sister-in-law has a 1997 Maxima GLE with 201K miles on it. She doesn't know what was changed, and what wasn't. So most likely, it's best to assume that everything is stock and nothing has been modified.

So, here's the problem. I'm driving the car, and while at idle, the car all of a sudden drops in rpm (ever so slightly), but returns to normal idle RPM instantly. And it keeps doing this off and on, sometimes more and sometimes doesn't do it at all. It FEELS like tapping the gas while driving and then letting it go -- that jerking feeling, with a slight drop in RPM.

No check engine light. And it seems to do this only at idle (but I could be wrong).

Fuel pump? Fuel filter? Any thoughts??

Thanks in advance!!

njmaxseltd

iTrader: (19)

Typical misfire, most likely a failing ignition coilpack. If it hasn't had a tune up, start there and make sure to get NGK spark plugs. Have the coilpack stalks checked for corrosion at the connection on the coil itself.

krmaxima

iTrader: (13)

Doesn't a misfire generate a check engine light (a code)?

ShocknAwe

iTrader: (3)

check the IACV hose and if it is in good shape then clean the IACV itself. Next do the plugs as they are more expensive. If you had a bad coilpack you would likely have a CEL but if it is on its way out then not necessarily

njmaxseltd

iTrader: (19)

If the coil is failing on the secondary side the ECU cannot see it. It can however, detect a misfire from the camshaft sensor (pos) by looking at the signal timing for a variance between cylinders. Much more difficult to calculate especially if its a random misfire.

Phromethius

as others have said, sounds like a bad coil. They sometimes will not offer any codes at all. But you described the bane of my car when I first bought it. My RPM twitch was ONLY apparent at idle. Giving it any gas or on the highway would get rid of it completely. Ended up being a faulty coil.

DBear

What njmaxseltd said. I had the same problem some time back, and it went away when I replaced my plugs with NGKs.

tslattery

I just fixed my 98 maxima today by replacing new MAF off ebay. I had cleaned my egr tube and IACV, put everything back together and reset ecm. Thought everything was great until car warmed up and idle would drop to 450-500 for a couple secs then back to normal. Drove me nuts for about a week. I cleaned my MAF because of the info on these forums but made no difference. I got a new off brand for $ 36 and change, probably made in china but installed today and idles perfectly. My maxima has 235,xxx miles and has been great. By the way the bad idle never showed and codes on my reader. I guess maf was just starting to go, but not gone. Also, my maxima stumbled in park and drive but driving was perfect. Hope this helps.

figueroa81

check the vacuum hoses to the map sensor or & the map sensor itself it looks like it going out