Just had my LTs, y-pipe, and catback installed

[98TransAmWs-6]

This may sound like a stupid question but how do I do a compression test or is that something a shop has to do? Also, if there is nothing wrong with cylinder 6 then why would I have the rough idle and can hear the cylinder miss?

[INMY01TA]

I ran a Granitelli maf way back in the day for about 5 months and it worked fine. Put Mac headers on the car and started getting misfires. I put the stock maf back on and sold the Gmaf, no more problems. Try running a stock maf.

[98TransAmWs-6]

I ran a Granitelli maf way back in the day for about 5 months and it worked fine. Put Mac headers on the car and started getting misfires. I put the stock maf back on and sold the Gmaf, no more problems. Try running a stock maf.

Know where I can get a screen for mine then? Cause I really don't want to buy the whole unit if I don't have to. But I am going to try replacing the fuel filter first before I do anything else.

[INMY01TA]

Know where I can get a screen for mine then? Cause I really don't want to buy the whole unit if I don't have to. But I am going to try replacing the fuel filter first before I do anything else.

no...

[35th-ANV-SS]

If you are getting a lean on both banks I almost guarantee that is a vacuum leak.

[98TransAmWs-6]

If you are getting a lean on both banks I almost guarantee that is a vacuum leak.

Its two codes for bank 2 so no not in both banks. But if it was a vacuum leak how would I fix that?

[35th-ANV-SS]

Well, I didn't read the entire thread I should probably do so real quick then report back.

[35th-ANV-SS]

You said you were going to clean your MAF....did you? P0174 code is most like a MAF or vacuum leak.

[98TransAmWs-6]

No not yet haven't had a chance to get the cleaner for it since I don't have any electrical cleaner

[35th-ANV-SS]

No not yet haven't had a chance to get the cleaner for it since I don't have any electrical cleaner

Try that first. Could very well be a dirty MAF. Get the MAF CR cleaner from Autozone, Pepboys, etc.

[98TransAmWs-6]

I finally just decided to take it to a shop and they found a vacuum leak in the tube from my egr valve to my intake manifold. I will be finding out what caused the misfire tomorrow.

[bberretta]

Try this: pull the spark plug wire and start it up- does it run any different? You need to trace the problem back to the root. By pulling the plug wire you'll see if the cylinder is even getting spark, if there's no change in the idle with or without the wire, then you don't have spark. Check the plug (electrical connector) going into the coil- most will pull the coil packs on the passenger side when they install headers.

[LS1_ws6]

I had the exact same problem when i did my headers. after a while motor would die, it had a crapy idle. I was told to look at the spark plug so i did and i found out i forgot to plug the #6 wire back in. tryed it and still misfired, i took a look at the coil connection and wasnt right, took it off and the thing inside was bent. I straightin it out put it back on and worked like a dream. might be your problem maybe not. just thought i would share my experience with the misfire.

[98TransAmWs-6]

The shop I went to said I have a clogged fuel injector and that's causing the misfire. Also, what even causes a clogged fuel injector? I would like to prevent this in the future.

[Too Fast]

Poor grade of fuel can do it, over a long time. I've always used Shell V-Power, never had a fuel related issue. Also, our cars don't have a return line for the fuel injectors, any "crap" that gets in there tends to go to the end of the line, like the even numbered fuel injectors. You might want to flush all the injectors, or replace them all, or just replace the #6 and have the others cleaned, off the car. Some ideas for you, obviously some cost more than others.

[bberretta]

It is strange that it suddenly happened when you had the headers done but it would explain the lean code.

[silverWS6]

It is strange that it suddenly happened when you had the headers done but it would explain the lean code.

But I thought headers make a car run rich and not lean

[98TransAmWs-6]

Poor grade of fuel can do it, over a long time. I've always used Shell V-Power, never had a fuel related issue. Also, our cars don't have a return line for the fuel injectors, any "crap" that gets in there tends to go to the end of the line, like the even numbered fuel injectors. You might want to flush all the injectors, or replace them all, or just replace the #6 and have the others cleaned, off the car. Some ideas for you, obviously some cost more than others.

Running on poor grade fuel isn't possible I always use shell v power. I suppose at some point I'll pull the other injectors and clean them.

[Y2KPewterSS]

But I thought headers make a car run rich and not lean

Headers do make it run rich, not lean.

[bberretta]

But he said that an injector was clogged, therefore he would be running lean. No fuel coming out = lean. No spark would equal rich.