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Old 01-07-2009, 04:25 PM
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Re: 99 4.3 Rough Idle, Low Temp, Bad Gas Mileage

Quote:
Originally Posted by dr_lee29
Well, I didn't get a list of tests that they ran on it but here is what they would like to do:
Clean the Mass Air Flow sensor (about $30)
Change the distributor and rotor (about $90)
Change the intake air sensor
And they want to change the lower manifold gasket because they say it has a vacuum leak on cylinder #4.
All told they want something like $450 to do the repairs.
This all sounds suspicious to me because the LMG is new! The rotor is new! And they just want to change the distributor because it looks old (its about 1 year old).
My question is, could a vacuum leak on the LMG cause a misfire on cylinder 4 without causing a misfire everywhere else? Is there a diagnostic test that they should have done to find this leak?

All of that does not sound quiet right.

Did you check them out first?
Have they got trained techs?

Maf sensor can be cleaned with a shot of MAF sensor cleaner or just unplugged for test.

Was fuel pressure tested good?

Have you got the temp back up to 195?

Any missfire codes?

Vacuum redings are good.
A injector balance test would be a good test to run.
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