Rough idle

[diver76]

Hoping for your help......

 

Here's the dilemma.

My 97 GMC sierra was having a rough idle and it was also time for a tune up. I did the tune up with all the good stuff like platinum plugs, cap and rotor, and even cleaned out the throttle body. I did everything but the wires at first and it still had a rough idle. I was planning on replacing the wires but it was expensive so it had to wait for next pay....

Every morning I start my truck and let it warm up for 5 minutes while I finish brkfast and when I climb in the "check engine light" is flashing....

As soon as I put it in gear and drive away. It goes away and I don't see it till the next morning. I have since changed my wires and replaced again with delco wires and it does the same thing. I have taken it to the dealer and asked them to check for any codes.

 

It found one code which failed 2 out of 3 tests.

It showed Mass Airflow Sensor.

 

Does this seem right. Has anyone had this problem before?????

The part is $500 plus Canadian.

Thats alot of money for the mechanic to say "its a good start to the problem?!?!?!?"

 

Thanks in advance

Sorry for the length of letter

 

Wayne

[97whitez71]

A fellow co-worker did exactly the same thing as you and changed all the same things. He took it to a local shop and they checked his fuel pressure and sure enough, it was his fuel pump going bad. They replaced his fuel pump and he said it has never run smoother. Now, his check engine light didn't come on, but this might give you something else to look at. Hope this helps.