The other night I was merging onto the interstate and my truck started acting funny. I went from 1 highway to another and accelerated to match speed. I did accelerate quickly but nothing abnormal. I have a 99 4.0 auto. Well once it was up to speed it started to hesitate, buck, and studar. When I got off at my exit it almost stalled. It was running perfect prior to this. Now it seems to lack power and idle rough. When Im driving it will buck and shake. If I accelerate or lay off the gas it smoothes out. Now when Im accelerating quickly or climbing a hill the check engine light flashes. Sometimes 9 times sometimes 16 times. I thought I got bad gas but I added some stabalizer. I dont think its the fuel filter because I can accelerate through the roughness. I dont think the cel is related also. I checked the air filter when it first happened and attempted to clean the MAF. Thats when the cel came on. Nothing like making bad even worse. I am going to order some MAF cleaner to try and save the MAF. This isnt going to solve my other issues. I am going to try a complete tune up, hope it helps. Anyone got any other suggestions? I hope its not a timing belt or anything else major. Any signs to look for? Thanks for the help.

 

Unplug the MAF and see if it improves. Unplug it when not running, then start it. If it can run okay, you have a MAF problem, if not, then get the code read.

The MAF, when bad, is still used and if the readings are off, the engine can't compensate. When the MAF is unplugged, the engine goes into an alternate strategy to control A/F ratio. It's not efficient, but it works well and the engine can run pretty well that way.

Give it a try. Get the code read if that doesn't do it. That's the simplest way to the problem.

 

The number of CEL flashes is not significant but the fact that it's flashing is. A flashing CEL means that the Misfire Monitor is detecting misfire in real time and that the misfire is sufficient to raise catalytic converter temperatures above the 1650F design limit. You need to get the code read to see whether the misfire is on a single cylinder or multiple cylinders or if it is random on all cylinders.

 

AH! I didn't even catch he said flashing!

 

Does this mean that something major is wrong in the motor? Or just wires, coil, etc?

 

I would guess an ignition problem of some sort or a lean A/F mixture.

 

Hmmm...okay well then he should still do the MAF test. If it's causing an artificially lean mixture that could do it. Worth a try since it's easy (one connector to unplug).

 

I noticed my truck has a weird smell as well. Kinda like something burning off or out. Thought it may be the cat. I am going to do a complete tune up. I havent changed anything since the issue so I hope the new tank of gas and tune up solve this.

 

Checked my wires lastnight in the dark with some water. They were arking REAL bad. I replaced the plug and wires today, cleaned the MAf. Then reset the code with my scanner. Truck runs great and no cel. I appreciate all the info. Thanks guys.

 

Good work! Glad you got it fixed.