Lq4 misfire issues
Thread Starter
Registered User
Joined: Nov 2017
Posts: 4
Likes: 0
Lq4 misfire issues I'm kinda new to these ls motors. I have an lq4 in an 01 3500 silverado mated to a nv4500 manual transmission. This truck was given to me with 146k miles. It sat in a field and didn't get driven much for 2-3 years. Once I took possession of the truck, I changed the plugs, filters, oil, and the battery. It ran pretty good before all that, but it would idle a little rough. It still idled a little rough after replacing that stuff. I eventually changed the knock sensors and harness, egr, temp sensor, and chased down some wiring issues from what I assume was rodents chewing on them. I've also recently replaced the fuel pump and one of the four o2 sensors. All these new parts are ac delco brand, as I havent had good luck with the stuff they sell at the parts stores I've put 50k miles on this truck since I got it. It starts every time and runs fine, but it still idles a little rough until the rpms get up to around 1000 +/-. I constantly have a p0300 code. The misfire isn't enough to trip the mil. It doesn't matter if it's cold or at operating temp. When I let the clutch out to take off, it wants to stall unless I give it a little more throttle than I like. I don't like to do this because I don't want to wear my clutch out. Once the rpms get up around 1000, it smooths out and runs fine. No problem at highway speeds, and has plenty of power. My next step is to replace the coil packs, and possibly the injectors. I'm not interested in deleting Things at the moment. I'd rather keep this thing as stock as possible. The truck currently has 196k miles as of today. Any help is greatly appreciated
TECH Senior Member
Joined: Jun 2016
Posts: 22,291
Likes: 3,616
From: Central Cal.
I have heard good about both. Techron is what Chevron puts in their gas, but is available in parts stores. You have to watch out when spraying in the intake; sometimes it will knock some carbon loose and stick in a spark plug gap, causing a miss. Just FYI.
Thread Starter
Registered User
Joined: Nov 2017
Posts: 4
Likes: 0
All the other o2 sensors are functioning properly, and it seems like the tps and maf sensors are working fine too. I do need to try cleaning the maf. Maybe I'll go grab some techron and maf cleaner today and see what that does
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
