Prozium

so I thought my transmission was to blame (automatic) so I looked up what problems I was having in the FSM. it pointed to the vacuum modulator so I bought a new one, and it did need to be replaced...but it didn't fix my problem.

It runs fine for a short time then it wont run for **** after (runs ruff and wants to die and will not pick up seed very well. let it sit over night and it will run fine again for a min or two then it wont run again.... I thought it was the tranny, but why would it work at all if it was blown...and why work fine then just stop working?

could it be something else? what should I be looking at?

it's an '87 base with auto tranny, all fluids are good, new NGK spark plugs.

rx-7 obsessed

compression check? during the 1 min it wants to idle does it idle nice and even or do you have to pump/hold the gas pedal during its good running time

Prozium

I meant drives fine, it has a vacuum leak somewhere, so idle isn't good tell it warms up, however after it warms up it idles fine... and like I said it runs fine for a few min then all the sudden it runs like crap and doesn't seem like it wants to shift, or at least that's what I assume it is doing... would it possibly do this if it dropped a rotor mid driving? like maybe I'm losing spark to a rotor?

Prozium

5 day bump....



also when it starts to run bad it almost acts like it's getting too much fuel and I have to take it easy on the gas pedal and let it work its way up.... any ideas?

Prozium

ok, one last bump....

also to add, it seems to only run bad when it heats up. tried again today and it ran bad from the start.(warm/hot day) any help would be great! haven't really been able to drive my car for over 4 months!

RotaryEvolution

iTrader: (30)

sounds like a plugged cat or fuel pump voltage issue.

check the fuel pressure and vacuum and watch them while this issue is going on. a plugged cat would show low vacuum even under no load situations. the fuel pump wiring is also notorious for having low voltage issues, it should be above 10v

Prozium

thanks for the tips. I will check in to them as soon as i can.

calpatriot

Sounds like your car is running rich (or, possibly, too lean) once it reaches temp and the ECU goes into closed loop. It runs rich during warm up, and then shifts into a normal mode once the radiator temp switch reaches its minimum value.

Look for:
Trouble codes
Closed loop operation check
Vacuum leaks
Idle speed and mixture adjustment
Check TPS values, dropouts, adjustment
Timing and advance
AFM resistance, dropouts
Intake air temp sensor
Check the BAC per the FSM procedure
Water thermo sensor

Quick way to check most of this stuff is to get down to the ECU, backprobe the connectors with a voltmeter, and compare the values to those published in the FSM ch 4.