I have a 2000 Silverado 5.3, A/T with 130K miles. I am noticing a slight miss at idle when dropped into gear. If you raise the RPM slightly the miss goes away. I have access to a SNAP ON Motis but have had very little training, mainly what I have taught myself. The miss does not set a code. At idle with Motis you can see a 20 to 30 count misfire per 100 seconds cycle, half occurring on number 5 cylinder. The others are random between the other cylinders. I have replaced spark plugs and fuel filter. I have not tried plug wires yet. What else could be causing this?

 

Have you cleaned the throttle body? They are notorious for gumming up and causing a miss. I had one not too long ago that would shut off from such an irratic idle. A can of throttle body cleaner and it ran like new again. If not an injector may be the culprit.

 

there are some on this forum who have had problems with lifters....and a bad lifter will cause enough of a miss to "notice" but not set a code that being said I would try wires first and clean the throttle body

 

Sounds like a clogged Injector. Check fuel pressure with a guage.

 

My 2000 gmc sierra 1500 just came from the shop because of a slight miss. I had the plugs replaced and it still has a slight miss. How do I clean the throttle body. The truck always starts fine the first time but subsequent starts take a crank or two. It also hesitates some times when I take off. Should I change the throttle position sensor. I am stumped but tired of paying 80 bucks for diagnosis that dont tell me ........ please help

ps- how do I change my idler arm. it is worn

 

Fuel pressure won't reveal a bad injector. Pressure is obtained before injectors.

Check your wires, make sure you don't have a broken boot or cracked jacket or something. Also check your fuel pressure regulator.

 

I was only suggesting to check fuel pressure. I was stating my opinion a to what I thought might be the problem. Checking fuel pressure will rule out whether it is the fuel pressure reugaltor, or fuel filter, or fuel pump, or a wiring problem. Which then can suggest if it is a fuel problem, then narrow it down to a possible clogged injector. Shoulda elaborated more my fault.

 

I wasn't trying to sound like a jerk, sorry.

All good ideas.