my 87 2.8 (for now) wont idle for crap when the engine is @ temp. new coolant temp. sensor & new maf...no light on!!! ant suggestions would be greatly appreciated.

 

Have you disconnected the battery for 5-10 minutes to let the ECM relearn the new readings from the MAF?

I'm not an expert on the fuel injected engines, but I've read that any changes in air sensing parts (MAF, IAC, etc) need to have the ECM wiped and let it relearn the proper idle.

I remember reading it should only take 2-3 starts and some driving for it to fine tune everything on it's own.

I'd also take a look at the IAC if you haven't yet.

 

thank you and not to sound dumb but what is this IAC??

 

Idle Air Control... Haven't dealt with it myself, as my car is carbureted, but I've read a lot on these boards, and that's what they always say to look at first when your idle is not behaving.

I'm sure someone more knowledgeable on the subject will chime in shortly.

 

1. No idle relearn pre-90. Nothing to worry about there. But, yes, disconnecting and reconnecting the battery is recommended.
2. You see the thing on the throttle body next to the black idle air pipe? The thing with 2 blue and 2 green wires? That's the IAC. Unplug it and unscrew it. Clean the end off and clean out the passage in the throttle body.
3. Check the vacuum hoses for being kind of chalky. If you touch one and your hand ends up black, they need to be replaced as they are deteriorating. Do the same for the rubber nipples on the ends of the idle air pipe running between the lower intake and throttle body. And the hose on the PCV valve. Check the fit of the PCV valve in the grommet to make sure it's tight. If it's loose, you may be able to replace it, or you may need to wrap electrical tape around the PCV valve to make sure it's tight in the grommet. Check the pipe connections to the pass side valve cover and the intake bellows as well. And make sure that the air box is completely sealed from outside air between the filter and the throttle body. Also check for an oil leak from the valve covers as this is a sign that they need to be replaced as they are also leaking air.
4. Failing #3, get a couple cans of starting fluid, hair spray, etc and start spraying around the vacuum lines, valve covers, and other things when the engine is stumbling to test for a vacuum leak anywhere else.

 

thank you all for the input it is greatly appreciated.