idle and engine response problem

[iam_jasonh]

hey guys i drive 89 eunos roadster,

not sure if this is a problem or not as i know shes an old car but before she gets to running temp (halfway on the heat gauge) she tends to skip a beat when i rev it, she idles at about 750. i rev her and the rpm's just drop to about 250 and if i rev her even harder she drops to almost stalling but she just holds on. Also when i rev her she skips a beat before it actually revs, kinda like takes a breath then revs and drops.

not sure if these are caused by the age or maybe an inner problem. the timing belt was just done and she was just serviced so i would have thought these problems would have been fixed.

HELP! any advice would be great thanks

[93_Clubman]

Details on my car in case its needed
89 Eunos Roadster
60000 kms on the clock
stock everything besides a Cusco strut bar

the timing belt was just done and she was just serviced so i would have thought these problems would have been fixed.

Start here:
http://www.miata.net/garage/KnowYourCar/S7_Idle.html
Depends what was included in the service - was it a minor or major service?
Baseline service (major service plus) is what's often required.
Btw, when timing belt was replaced did they also replace the water pump?

[iam_jasonh]

Details on my car in case its needed
89 Eunos Roadster
60000 kms on the clock
stock everything besides a Cusco strut bar

the timing belt was just done and she was just serviced so i would have thought these problems would have been fixed.

Start here:
http://www.miata.net/garage/KnowYourCar/S7_Idle.html
Depends what was included in the service - was it a minor or major service?
Baseline service (major service plus) is what's often required.
Btw, when timing belt was replaced did they also replace the water pump?

it was a major service so everything and waterpump and hoses replaced too

[93_Clubman]

Good to hear they did the water pump when doing timing belt, but as you say it seems their major service didn't detect or correct the current problem.
A baseline service would involve:
List for NA8:
check/ replace engine oil, oil filter, & sump plug crush washer (every 6 months)
check/ replace gearbox oil, including turret (every 2 years)
check/ replace differential oil 75W-90 (every 2 years)
check/ flush/ replace brake fluid (every 2 years)
check/ flush/ replace clutch fluid (every 2 years)
check/ flush/ replace coolant in radiator & expansion tank (every 2 years)
clean/ replace air filter (every year)
replace fuel filter (every 2.5 years/50k kms)
check/ clean/ replace 4 sparkplugs NGK BKR5E-11 (every year)gap=1.1mm
check/ replace spark plug leads
check & clear ECU codes by disconecting battery
check/ clean/ adjust idle screw 850RPM +/- 50RPM
check/ adjust timing - 10 degrees BTDC
check/ replace CAS O-ring
check rear main seal drain hole
check/ adjust throttle cable freeplay 1-3mm
check/ clean throttle body & fuel injectors
check/ clean MAF element
check/ clean PCV valve
check/ clean restrictor operation
check throttle position sensor
check/ replace O2 sensor
check evaporative system
check/ clean cold start pipe fittng & connections
check fuel lines & hoses
check/ adjust/ replace alternator belt 4PK885 - new / used belt: 8-9mm / 9-10mm deflection with moderate pressure
check/ adjust handbrake
check/ adjust clutch pedal freeplay
check/ adjust brake pedal freeplay
check/ adjust front & rear wheel alignment
check/ adjust wheel balance
check/ adjust wheel nut tightness
check/ fill washer bottle level
check/ adjust/ replace tyres & pressures
check/ replace wiper inserts (annually just prior to Winter)
check/ replace front & rear brake pads, grease caliper slider pins & machine discs as necessary
check/ replace timing belt (every 100k kms)
check/ replace waterpump (best replaced in conjunction with timing belt)
check/ clean power window switch contacts
check/ tighten hardtop latches securing screws
check/ clean inside front lower quarter panels
check/ clean windscreen cowl drains & ventilation intake
check/ clean soft-top drains & drain pipes, as well as sill drains & front windscreen frame rubber side drains
check/ clean battery terminals & under battery tray for rust
check/ clean underbody
check/ clean boot, especially boot floor & arms for water or rust
check/ clean engine bay
check/ clean interior, especially parcelshelf & floorpan for water or rust
check/ clean/ polish exterior
check cooling system
check/ replace inner & outer gearshift boots & gearshift base collar/ cap
check brake lines, hoses & connections
check clutch line, hose & connections, including slave cylinder
check/ adjust/ replace front wheel bearing freeplay
check engine mounts
check steering operation & gear housing
check steering linkages, rack guide & tie rod ends
check front & rear suspension ball joints
check/ tighten bolts & nuts on chassis & body
check/ replace driveshaft dust boots
check tighten exhaust system heat shields
check/ tighten exhaust manifold bolts & nuts
check/ replace damper dust boots
check/ replace fuel pump wiring harness top tank connection
When present:
check/ adjust/ replace AC & PS belt - new/used AC belt 8-9mm / 9-10mm deflection with moderate pressure
check/ adjust/ replace powersteering fluid & lines
check adjust/ replace automatic transmission fluid

[iam_jasonh]

Good to hear they did the water pump when doing timing belt, but as you say it seems their major service didn't detect or correct the current problem.
A baseline service would involve:
List for NA8:
check/ replace engine oil, oil filter, & sump plug crush washer (every 6 months)
check/ replace gearbox oil, including turret (every 2 years)
check/ replace differential oil 75W-90 (every 2 years)
check/ flush/ replace brake fluid (every 2 years)
check/ flush/ replace clutch fluid (every 2 years)
check/ flush/ replace coolant in radiator & expansion tank (every 2 years)
clean/ replace air filter (every year)
replace fuel filter (every 2.5 years/50k kms)
check/ clean/ replace 4 sparkplugs NGK BKR5E-11 (every year)gap=1.1mm
check/ replace spark plug leads
check & clear ECU codes by disconecting battery
check/ clean/ adjust idle screw 850RPM +/- 50RPM
check/ adjust timing - 10 degrees BTDC
check/ replace CAS O-ring
check rear main seal drain hole
check/ adjust throttle cable freeplay 1-3mm
check/ clean throttle body & fuel injectors
check/ clean MAF element
check/ clean PCV valve
check/ clean restrictor operation
check throttle position sensor
check/ replace O2 sensor
check evaporative system
check/ clean cold start pipe fittng & connections
check fuel lines & hoses
check/ adjust/ replace alternator belt 4PK885 - new / used belt: 8-9mm / 9-10mm deflection with moderate pressure
check/ adjust handbrake
check/ adjust clutch pedal freeplay
check/ adjust brake pedal freeplay
check/ adjust front & rear wheel alignment
check/ adjust wheel balance
check/ adjust wheel nut tightness
check/ fill washer bottle level
check/ adjust/ replace tyres & pressures
check/ replace wiper inserts (annually just prior to Winter)
check/ replace front & rear brake pads, grease caliper slider pins & machine discs as necessary
check/ replace timing belt (every 100k kms)
check/ replace waterpump (best replaced in conjunction with timing belt)
check/ clean power window switch contacts
check/ tighten hardtop latches securing screws
check/ clean inside front lower quarter panels
check/ clean windscreen cowl drains & ventilation intake
check/ clean soft-top drains & drain pipes, as well as sill drains & front windscreen frame rubber side drains
check/ clean battery terminals & under battery tray for rust
check/ clean underbody
check/ clean boot, especially boot floor & arms for water or rust
check/ clean engine bay
check/ clean interior, especially parcelshelf & floorpan for water or rust
check/ clean/ polish exterior
check cooling system
check/ replace inner & outer gearshift boots & gearshift base collar/ cap
check brake lines, hoses & connections
check clutch line, hose & connections, including slave cylinder
check/ adjust/ replace front wheel bearing freeplay
check engine mounts
check steering operation & gear housing
check steering linkages, rack guide & tie rod ends
check front & rear suspension ball joints
check/ tighten bolts & nuts on chassis & body
check/ replace driveshaft dust boots
check tighten exhaust system heat shields
check/ tighten exhaust manifold bolts & nuts
check/ replace damper dust boots
check/ replace fuel pump wiring harness top tank connection
When present:
check/ adjust/ replace AC & PS belt - new/used AC belt 8-9mm / 9-10mm deflection with moderate pressure
check/ adjust/ replace powersteering fluid & lines
check adjust/ replace automatic transmission fluid

wow big list o.O but thanks for the help man, really appreciate it