Stalling and misfire possibly due to air intake

[Jdog]

Hello,

I have a 98 ranger 3.0. Two weeks ago I was getting a code for bank 1 lean. I replaced the air duct because it had a large tear and was held together with tape. I cleared the code and the code hasn't come back.

After driving it for two weeks without issue I tried turning it on yesterday. The engine would turn over but stall after a few seconds with no check engine light. I got it towed home and today I have been troubleshooting with the air intake.
I removed the air duct from the throttle body and the engine was at least able to stay running with a horrid misfire. When I tried to open the throttle it would stall. A code for air intake temperature came on but that is because I disconnected the sensor to remove the air duct. I then removed the idle air control valve and plugged up the air passage to the intake manifold with a rag. I started it again and it started out rough but once I opened up the throttle the misfire went away and I was able to increase and decrease rpms without issue. I thought I had it figured at that point (bad IACV), but when I turned it on later under the same conditions the bad misfire wouldn't go away and would stall when I opened the throttle.

Am I going down the wrong road looking at the air intake? I doubt that its a fuel/electrical issue but I'm not sure what more to explore on the air side. Other than a sensor that I'm not aware of.

If anyone has experience with this issue I would greatly appreciate the input.

 

[O No 3.0!]

Too much air isn't going to cause a misfire, it would more likely be a bog or stumble. I would start by checking your spark plugs to see if you can tell which cylinder(s) are misfiring. Mine did the same thing awhile back & it was the coil pack.

 

[rubydist]

Look at what the codes are - that will help guide you so you are not just guessing.

 

[ericbphoto]

Also, if it was an air intake problem, that should affect both cylinder banks. The code you had at the beginning was just one bank.

Second, with the intake tube disconnected, your MAF can't tell the engine how much air is being drawn in. That causes issues.

The IAC is there to provide air when the throttle is closed. So plugging that while it's removed will affect idle. With throttle open, you want the IAC shut.

You need to pull fault codes. Even if the CEL is nor on, there still may be fault codes to help figure out what is or is not wrong.

 

[Jdog]

Thank you all for the advice/suggestions. It turned out to be the MAF sensor. I didn't think it could cause stalling/bad misfire. But when I unplugged it the misfire almost completely went away. Then after replacement its back to normal.

Thanks again.

 

[helpme]

I need a new intake duct on my 94. Only found one on ebay for $57. Any other supplier out there?