[an_juan]

Hello,
My car idles great when it is cold (during warm up), and pulls a healthy 21 inches of HG. Once it's comes down to normal idle (1K rpm), it begins to sputter. The engine shakes horribly when I open the throttle and it seems to run very rich. I replaced new plug wires and new spark plugs; still the same. Please help me.
Thank you.
A.T

 

[tHa kNiGHt FaLL]

how much vacuum at wide open throttle...?
how much vacuum when the idle drops down to 1k?

sounds like the motor is starving... check your mass airflow... not enough air...

 

[WT Morgan]

Check the cold start valve also. It could be dumping lots of extra fuel in after warm up also. You might disconnect it and see if that fixes the problem.

 

[MRQtwinturbo]

check your timing...have you done anything to it recently??.....

 

[an_juan]

I disconnected the cold start injector in the manifold; same thing happens.

It seems to hunt during the sputtering episodes. It would idle ok for a couple seconds, then sputter, then idle ok for a couple seconds, then sputter.....

Vacume never drops below 18.

This started happening all of the sudden. I didn't do anything to the car recently that I could attribute the problem to.

When it runs cold after start up, it runs absolutely fine with out any problem.

I didn't check the timing.....I guess I should do that.

I think the thermostat is stuck open because it takes a looooong time for the temp. needle to come up. When I drove the car (a few months ago), it would take about 15 minutes for the needle to be at normal temp.

 

[tHa kNiGHt FaLL]

vacuum should go alot lower than 18 at wide open...

 

[WT Morgan]

Keep chipping away at whatever you find. Fix the thermostat and check for any vacuum leaks, loose wires and connectors, etc. It sounds like you may be into a MAP sensor problem. What hapens if you disconnect it? Get a copy of the manual and start through the troubleshooting steps. Post what you find. Good luck.

 

[WT Morgan]

mr2-tech.com has a whole manual set for reference.

 

[tHa kNiGHt FaLL]

you have to have a vacuum leak of some sort...

air is leaking out before it reaches your intake manifold... cause not enough air to enter the cylinder.... which would make it run rich... and idle poorly...

and thats why you have constant manifold pressure even when your not supposed to...

check the vacuum lines on the manifold... check to see that you MAF sensor... because its a vane type it has that swinging door... make sure the door moves... put a voltmeter on it and make sure the voltage sweeps... and check your air filter

 

[an_juan]

thanks fellas,
the water temp sensor partially broke off (at the rubbery part). The ecu might not be reading rising water temp, so it continues to dump fuel as if the engine is still cold. I'll play with this sensor this weekend and see if anything changes.

 

[tHa kNiGHt FaLL]

thanks fellas,
the water temp sensor partially broke off (at the rubbery part). The ecu might not be reading rising water temp, so it continues to dump fuel as if the engine is still cold. I'll play with this sensor this weekend and see if anything changes.

yea that will keep the ECU from going into closed loop...