Hey guys,
I have an 88 FSB that I can't keep at idle. When I start it the RPMs start to fluxuate and will eventually drop so low that the engine dies. I CAN give it plenty of gas and keep it idling at 500-1k rpms, and it will drive. However as soon as I let off the gas the rpms just drop and it dies. It will start every time as long as I give it gas. I have a slight exhaust leak, and the check engine line has been flickering on an off the past few days but now it stays solid when the truck is on. It doesn't feel like a fuel pump or filter problem.. maybe a sensor of some sort? I felt the exhaust, it doesn't feel restricted at all.

my first responce would be to run codes and see what it says, but a good place to start would be a hole in the intake tube if it is a MAS air motor. the hole will be between the MAS air meter and the throttle. if you find a hole use some duct tape to cover it untill you find a new one. check the hose clams and make sure they are tight also.

no MAF on a 88 bronco....

Our 89' bronco plow rig had the same problem..

after a few months it went away.. However, there was a PIP code showing on it.. so suspect that may have been the cause.

run the codes perry, if ya need help on how to do that let me know and i can drag the write up from FSB to here

wes

check you idle air control valve. alot of gunk that gets through the filter will collect there. just pull it and clean it out with some cuetips. Another thing it would be is the EGR valve or the sensor itself...if your exhaust was runnin rich you would plug up the lil pintle on the end of the valve. Pull off the valve clean it up. another thing it would be is the pip, TfI, or the O2 sensor. Run the codes and see what it pulls up

if I am not mistaken the PIP is in the distributor modual. you can take that off and have it tested at autozone. they will also run codes for you for free. the IAC was a good call I forgot about that. with EFI you are kinda shooting in the dark when you have a problem unless you pull codes.

tps...throttle positioning sensor..$35..

check you idle air control valve. alot of gunk that gets through the filter will collect there. just pull it and clean it out with some cuetips. Another thing it would be is the EGR valve or the sensor itself...if your exhaust was runnin rich you would plug up the lil pintle on the end of the valve. Pull off the valve clean it up.

This is where I'd start.

Thanks for all the help guys, I have no idea where any of this stuff is located.

go to part store buy chiltons or haynes book for your bronco look in the fuel system chapter it will show you were these parts are located

Got it to run, I cleaned all the carbon out of the throttle body and she started right up. I did pull the following codes however:

5 - 2 - 5 - 2 - 1 - 1 - 4 - 5 - 1 - 3 - 3 - 1 - 4 - 5 - 1 - 3 - 3

Am I correct in seeing something wrong with the powersteering pressure switch and EGR valve?

go to part store buy chiltons or haynes book for your bronco look in the fuel system chapter it will show you were these parts are located

get the haynes manual. it will give you the ohms of resistance that each of your sensors should be putting out when working right.

Ttt