vibration (engine?)

[downtempo]

Hey folks,

My '91 Q recently started a new vibration, maybe more of an engine shudder. Idle in D is 600, little hesitation on intial gas input, engine seems to be a bit down on power and struggles, shuddering (not horrible, but noticeable) until aprox 1000-1100 rpm, smooths out until 1750, shudder comes back and smooths out again above 2100rpms. happens in gear and in neutral. Any suggestions would be appreciated. Car does vibrate at idle as well. Hope it's not another injector.

Have also been some mileage runs and seem to only be getting 12-13 mpg. All driving is city (short start and stops) with liberal does of my size 12. Also, does anybody work on miata's? Or know of a good message board for them? Met a girl with a 1997 miata, 89K and CEL light on, her mechanic "checked it out" and said she doesn't have to worry about it right now, can drive with it, and reset the light. It came back on within 24 hours. Would love to impress her a bit.

thanks

[qship96]

for the miata,try http://www.miata.net very active forum,use it for the wife`s 99 all the time.

[downtempo]

thanks for the miata site.

My Q feels like it's having a hard time pushing past 2K rpm, but once past is ok.

Any thoughts?

[Q45tech]

Dirty plenum, throttle body, spark plugs, knock sensors. Get a Consult Diagnosis from a certified Infiniti tech who is expert on the car model.12-13 mpg is a little low for all stop and go with AC and size 12.....but that depends on fuel [oxygenates]. If it gets 22+ on a long trip you know the city mileage is your fault.

[texasoil]

just got back from 600 mi trip @78-80, mostly interstate,but a few WOT's. avg 21.5 MPG, A/C loaded all the way (98F, 90% humidity) 94 Q45active,135K miles

[Chally]

Also check the cleanliness of the Air mass meter terminals. Make sure they are shiny clean on both the Meter & the harness.