Continued Idle surge

[sohcsol]

I have 1991 XLT and have been through an array of parts solving a very poor fuel economy problem. After a new ECM, ECT, IAC, and a thorough cleaning of the throttle body, IAC, and MAF wires the fuel economy has gotten much better, but I still have an idle surge which tends to show up once the vehicle is warm and only every once in awhile. it surges from about 550-800 RPM, and shortly after the check engine light comes on. Pulled codes (engine on) and recieved:

79: MAP/MAF/Baro insufficient change during goose test

SHould I try cleaning the MAF wires again or lok at the Baro sensor? Don't have a volt meter with an "hz" setting to test the Baro so I am hoping for some guidance. thanks

 

[ExplorerDMB]

barometeric pressure is probably not the issue. You more than likely need a new MAFS. If your hurting for money - a used one. That would be my best bet.

-Drew

 

[bstone]

I just replaced me MAFS with a reman. $100 retail and then I got $30 for the core, so $70. It is a major improvement alreayd and all but 10 minutes of work.

 

[sohcsol]

I'll give it a try, thanks for the help.

 

[Maniak]

I didn't see testing the TPS as something you did.

There is even a thread on how to adjust it for better throttle repsonse on the site, but in general, you want to make sure that voltage doesn't move when the throttle is closed, and that as you open the throttle that the voltage increase slowly, and smoothly (matching you opening the throttle)

BTW.. to check the hz of the baro sensor you can use a tachometer set to 6cyl.. (I just had to do that to check a MAP sensor on an 88 ford)

~Mark