as above..Ihave a 1988Mazda 13b non turbo auto,,, funny thing is it runs awesome till it gets warm then won't rev over 1500rpm.. nofluid leaks at all or prestone smell... it is like it runs out of fuel ..then catches etc. Fuel filter is new...I am stumped.

 

Check your tps, throtle position sensor, its on the front of the throtle body it's a little black box w/a black plunger comming out towards the driver side. Get a multi meter and, with the positive lead, back probe the red/green wire on the connector. Put the negative lead on any good ground. Set the meter to DC volts, you should get a reading of 1 vdc. If not, adjust the tps screw until it is. Make sure your engine is FULLY WARMED UP before you do this!!

 

Hi ghomer,
First off I would hold off on the tps adjustment, tps units do not normally just jump out of adjustment for no reason, there will be obvious signs of a mechanical failure around the linkage or mounting brackets, or if it failed internally you will want to verify it first, then replace the unit, holding off tweaking screws till it is absolutely needed as it would only complicate things later... also, it has been a little, while but to the best of my memory a problem with the tps would normally manifest itself with the engine cold or hot...
Now, have you done anything under the hood recently, tuneup, componant replacement, degrease it, etc? If so, start looking real close in those areas you worked in for loose hoses, electrical connections or anything that may have changed since it ran well last. Use the factory vacuum line diagram to verify the location of vacuum hoses that may have been messed with...
Also there are vacuum circuits that only become active after the engine comes to temp, so check all the hoses, check thoughly, especially for cracks under the hose connections (seen them split under the hose just out of sight),.
Check carefully around the main intake hose between the air inlet box and the throttle body, I have seen these develop cracks in them that open up only when the throttle is opened and the vacuum tries to collapes it (remembering that during engine warmup the air/fuel ratio is rich so during this period a small leak may not be noticed but once warmed up it will cause a lean condition due to air bypassing the air metering door not being compensated for by the ecu)...

You say this happens only after warmup, what does it do exactly, such as - it will not rev beyond 1500 but stays at 1500 regardless of throttle, or it dies after 1500 if throttle is held open, or rpm begins to oscilate rapidly anytime revs pass 1500 (like someone turning on and off the ignition), or the revs will climb but only if very light throttle is applied... does it do it all the time or only when in drive, etc, you are our eyes, ears and hands so try to relay your observations as accurately as you can...these are just a couple thing to start with... hope it gives you a good start...

 

Do you have/still have the cat(s) installed on your 7 ?

 

[QUOTE=GORacing]also, it has been a little, while but to the best of my memory a problem with the tps would normally manifest itself with the engine cold or hot...
QUOTE]

Right, and that is what he is saying. It runs good cold and crappy when it warms up. The cold start thermowax holds the tb open a little until the engine reaches temp. This could cause the tps to be right on and once it gets hot that good reading goes away. Thats why you only check the tps when your're at operating temp. It takes 8 sec. to check anyway so theres no reason not to. A good reading is 1vdc when the engine is fully hot. Just my opinon though, I'm no genius.

 

i bet u have a valve getting stuck due to carbon build up i dont think a tps would make it cut off at 15k im willing to bet money that you have carbon build up itsa common with rotaries but that valve is hard to find mazda had to make 1 for me

 

me too

those pesky valves are really tough to find!