Filled up with gas Casey's now won't get up to speed. Bogs down when downshifting

BIKERHAL27

MEMBER
2000 CHEVROLET ASTRO
156,000 MILES

At first after filling up tried to get up to highway speeds, check engine light started flashing until I let off gas pedal. Showed P0300 and P0101 codes. MAF seems to be working Three wire connector puts out 2500hz and and increases steadily with rpm increase. Put new fuel filter on but no change

2 Replies

MERLIN2021

MECHANIC
17,250 POSTS

How are the plugs and wires? P0300 is random multiple misfire code, and will cause catalytic converter damage if you drive it like this, Tune up parts are the first step.

Was this

answer

helpful?

Yes

No

Friday, March 9th, 2012 AT 9:51 PM

MERLIN2021

MECHANIC
17,250 POSTS

The other thing Yoy will find is, if you are using a K&N air filter that is oiled, you will have MAF problems, replace the MAF and retest.
Shop: BIG DAVES AUTOMOTIVE
Date: 1/28/2008 12:59:48 PM

This tip pertains to the 4.3L Vortec's found in the 1996-2001 Blazers. Symptoms: Sluggish off-idle acceleration, pop or backfire through exhaust, no MAF codes, or DTC 101, almost as if the timing is off a little. The two parameters you should be concerned with is Hertz frequency on the MAF, and the gm/sec airflow of the meter. On a good running 4.3 with a throttle snap to about 3500 RPM you should see readings of about 80 gm/sec at about 7000 Hz, for example if you get readings such as 55-60 gm/sec at 6000 Hz this will defiently give you the above mentioned symptoms, with no codes.I.E. In-range failure. Hope this helps!