Hello everyone, I am needing some help with my 2000 Blazer LS 2 door. It has the 4.3 which seems to be a pretty good engine but I have a couple of concerns.

First concern is you can smell raw fuel when driving, (basically rich condition). It's not all the time but hit and miss. Mainly only when on the highway and under hard accelerating. Any ideas what might cause this?

Second concern is when I first start the truck up after sitting for say 8 hours or a typical sit while I'm at work I'll let the truck idel to warm up a bit before I drive it but as soon as I put the transmission into drive and start to accelerate the engine and/or transmission stumbles for just a split second then it's fine the rest of the time I'm driving it. Any ideas what this might be?

Third concern is when I was changing the air filter I went a head and took off the entire air intake assymbly from the air filter box upto the throttle body. I noticed that in the throttle body itself it seems to have a thin layer of built up dust or possibly mud. Thinking worse case here if the engine did ingest some water and or mud at some point in its life before me getting it. What would I want to think about or consider replacing/repairing to make the engine last? Any help with the concerns would be greatly appreciated. Thanks in advance.

 

Are there any codes present or pending?

How bad is the stumble? Is it only when the transmission is in 1st gear or will it do it if backing up as well? Does it appear to be related to a certain throttle position?

As far as the buildup in the throttle body, I doubt that it had injested mud or even water for that matter. It likely is just carbon buildup from the EGR system. Removing the TB and giving it a good cleaning would be the only recommendation I would give.

 

Hi Swartlkk. The truck has no computer codes for anything. The last code it had was about 2 weeks ago and it was for the fuel tank pressure sensor. A buddy of mine was nice enough to help me replace it and all has been well since at least with the check engine light anyway.

The stumble is litteraly just a split second. It only does it in first gear under normal acceleration. If you give it alot of trottle it doesn't do it but then you get the fuel fumes smell bad.

 

Just for giggles, have you tested the TPS sensor? The output wire from the TPS sensor to the PCM should read ~0.5V at closed throttle and ~4.5V at wide open throttle and be a smooth transition between the two throttle positions in both directions. Test the dark blue wire by inserting a back probe fitting past the weather pack seal (a small paper clip with the end rounded using a file or sand paper can function as a back probe fitting in a pinch) leaving the connector on the TPS sensor.