[J_Rod]

I'm using my sisters 97 4x4 Blazer while I'm truckless Its got some problems though. It just recently got the fuel pump replaced about 2 weeks ago after being undriveable for about a month. It runs now, but its got a horrible idle, hesitates from a stop, and has a blinking SES light. My buddy rans the codes and it has 3 O2 sensor codes (2 inactive, and one heat circuit error) and a misfire on cylinder #1 (p0301)

We're assuming that the misire is the main problem, causing the o2's to go wacky from being rich from either no spark or a stuck open poppet. Am I close? I only suspect the injector because a.) its got close to 150,000 miles b.)heard many stories on these forums about stuck poppets and c.) one of the mechanics that first looked at replacing the fuel pump said to replace the injectors as well (though the other mechanic that did the actual work said the injectors were fine).

I relaced The plugs and wires about 3 years ago, but I used cheapie autolites and wal-mart wires (not my truck, not my dollars ) so i guess those could be the culprit as well.

anyone else have this code? what fixed it for you? HELP! MKgearhead...where are you at buddy!? This is your specialty.

 

[J Tom]

I had the same code on my 98. Had a very rough idle/midfire. turned out to be the plugs. So maybe pull one and see what it looks like.

 

[jmhouston80]

I had the same thing on my 96. I had the following changed out: plugs, plug wires, distributor cap and rotor, coil. Did not help any, it still had a rough idle and misfire in cylinder 1. Mechnic found it to be a leaking fuel pressure regulator, replaced it and now it's running like a champ. Although now my catalyc converter is shot.

 

[BlazerLT]

Check your cap and rotor.

When were they replaced last.

Probably the culprit.