Extremely lean fuel trim blazer 2000 chevrolet v6-4.3l

Q: Extremely lean fuel trim

asked by on July 13, 2017

Car has been getting terrible gas mileage and is very sluggish throughout entire acceleration. Plenty of hesitation as well. Maf readings are in spec as well as O2 sensor readings. Initially I thought low fuel pressure but the ltft stays between +20-+25 no matter the rpms the only time it seems to go down is about half way through the acceleration of a gear, say around 2000 rpms and even then jumps between +15-+20. I would expect a low fuel issue, that is not bad enough to cause stalling and more serious issues, to not be as present at idle. I do not have a fuel pressure gauge by the way and do not want to go out to buy one to test the fuel pump before I figure these readings out. I don't understand how THAT lean of a condition can stay relatively the same at idle as it does through out entire acceleration, all the way up to wot throttle there is little variance. In addition bank 1 and bank 2 are identical so clogged injector is out of the mix in my opinion.

My car has 150000 miles.
My car has an automatic transmission.

Hi there. After completing an error code download to verify if this is an electrical glitch first, the next step most professional mechanics would complete is the fuel pressure test. This tends to be the source of an across the board fuel pressure reduction and can be caused by debris in the fuel line, clogged fuel filter or a fuel pump / pressure regulator that is faulty or also clogged with debris. Since your Blazer is nearly 20 years old, it’s quite possible that debris from years of gasoline and carbon deposits are causing this issue. However, without completing the fuel pressure check, you’re likely to keep running into diagnosis issues.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Cold Starting Problems

As a general rule, car engines do not like cold weather and do not do operate as well in cold weather. When you start your car in the morning and turn the key to on, the coolant temperature sensor immediately...

AC makes noise after putting on expansion valve

Hello. It sounds like your new compressor may be failing. Flushing the system is not enough when the compressor fails. When there is debris in the system, it gets stuck in the expansion valves, the condenser, and the accumulator. If...

I started my car today and realized that the wipers, signals, lower driving lights and heater blower had all stopped working.

Hello and thanks for your question. there could be a blown fuse for the ignition switch or relay. Plus, look under the hood for any rats or field mice nests. Field mice like to chew through wires causing all kinds...

Related articles

2012 Chevrolet Traverse vs. 2012 Toyota Highlander: Which One Should I Buy?
Large SUVs are a huge and broad market, with a range of different offerings from economy to luxurious. The majority of the SUVs and crossover SUVs offer decent gas mileage, plenty of room for friends and family to ride along...
A Buyer’s Guide to the 2012 Chevrolet Tahoe Hybrid
Chevrolet Chevrolet has always had a good name when it comes to the vehicles they make, and that is doubly true for their SUVs. The 2012 Chevrolet Tahoe Hybrid has all of the great features that you would want from...
A Buyer’s Guide to the 2012 Chevrolet Silverado
While While the Ford F-150 is still the best-selling pickup truck in the US, the 2012 Chevrolet Silverado is one of the finest half-ton pickups available today. In fact, the Silverado and the GMC Sierra are actually the same vehicle...