Okay, I just did what's considered a minor tune up on my DD (1993 Nissan Sentra GXE). I'm one of those ***** that gets peace of mind from overkill. I did iridium plugs torqued to spec, Mobil 1 5W-30 oil and filter, OEM fuel filter and K&N air filter. We inspected the motor and tranny mounts and they're perfect. I'm getting a motor vibration, one that translates through to the exhaust and rattles the heat shield on the primary pipe off the manifold when it comes down from driving RPM's to idle RPM's at at light etc. The car has 98,000 dealer serviced KM's on it. It seems to idle rough at times, not so much that it's a big deal but I know I should be able to rest a beer on the motor and it still hold carbonation. The thing runs perfectly otherwise and that's what bothers me. The motor SHOULD be silent and it ain't. In the owners manual it states that idle speed may compromise overall performance. Could that be all it is or should I be looking at the disty and wires (which look golden upon inspection BTW)? I know it's a Nissan but running problems are running problems so I thought I'd reach out. Any advice would be appreciated. The vibration can be felt through the gas pedal when the car shifts into O/D while lugging (up a hill) or when I probably should have the automatic O/D button disengaged when traffic is slow. If the car is idling in "P", if I press my foot against the tailpipe the vibration translated through to the exhaust is significant. All exhaust, tranny, and motor mounts are in order both in condition and tension. I'd rather go to a prostitute than a mechanic, any ideas???

 

'Lil help...anyone?

 

Had the same problem on my friend's Saturn SL-1. Check your coil packs, IAC, TPS, EGR and check for vacuum leaks. Spray some intake cleaner around your vacuum lines and around your inake manifold. If the idle rises, you sir, have a vacuum leak from one of your lines or your intake manifold gasket.

 

If you already went through the basics like plugs, filters etc. Just take it to a Nissan specialist. I've fixed everything fixable from 60's cars to 2000. Cars are just getting harder to diagnois everyday.

Instead of throwing parts at a perfect car that has ONE irritating problem. At least have a computer diagnoistic check and go from there.

If it's just a slight vibration, find another Sentra with the same engine and see if that's smooth. Some 4 cylinders will vibrate and be considered working 100% normal.