1999 suburban misfires plz help .......... yup im going there
Thread Starter
CF Beginner
Joined: Jul 2016
Posts: 2
Likes: 0
From: island off ny ... the long one
1999 suburban misfires plz help .......... yup im going there
just picked up this truck for a decent price , got it because previous couldn't fix it and gave up
its a 1999 suburban 137k 5.7 vortec
ok did all the basics ....... all cyn compression is at 170 , new distribitor, new wires, plugs, new updated spider, new MAF, new coil, new IAC motor
previous owner did intake gasket, replaced ecm and had it programed
I checked with noid light at the harness to spider all good, checked for spark with spark tester all good, fuel pressure 60 psi
right now have p0300 , with dead misfires being at cyn 5 & 7 and it almost feels like when the truck warms up it gets worst
I have googled and binged everything and im at a loss ..... thinking im overly frustrated and cant think straight anymore so any help i would be very thankful
its a 1999 suburban 137k 5.7 vortec
ok did all the basics ....... all cyn compression is at 170 , new distribitor, new wires, plugs, new updated spider, new MAF, new coil, new IAC motor
previous owner did intake gasket, replaced ecm and had it programed
I checked with noid light at the harness to spider all good, checked for spark with spark tester all good, fuel pressure 60 psi
right now have p0300 , with dead misfires being at cyn 5 & 7 and it almost feels like when the truck warms up it gets worst
I have googled and binged everything and im at a loss ..... thinking im overly frustrated and cant think straight anymore so any help i would be very thankful
CF Beginner
Joined: Jun 2016
Posts: 7
Likes: 0
Have you changed the air filter?
Have you changed the air filter and cleaned the Mass Air Flow sensor?
the only reason i ask is that I was having what i thought were fuel intake problems, I changed my filter and a couple fuel lines, dumped in fuel additive and I started having backfires and sluggish performance like a fuel line was blocked.
It turned out to be a dirty Mass Air Flow sensor and I fixed the problem for about $8.00 (Cost of a can of Mass Air Flow cleaning spray.)
the only reason i ask is that I was having what i thought were fuel intake problems, I changed my filter and a couple fuel lines, dumped in fuel additive and I started having backfires and sluggish performance like a fuel line was blocked.
It turned out to be a dirty Mass Air Flow sensor and I fixed the problem for about $8.00 (Cost of a can of Mass Air Flow cleaning spray.)
