Diagnosis help PLEASE

[Clydez7]

I got a 99 ranger super cab 2wd manual 3.0. As long as the maf is plugged in it stumbles and jerks and won't make power above 2000 rpm. Have replaced cam synchronizer, egr valve and differential pressure sensor and an o2 sensor. The maf and tps both check out good on multimeter. As long as maf is unplugged it runs decently but won't idle sometimes. When it dies it smells like it's running lean. Help

 

[Bgunner]

Have you cleaned the MAF sensor? They make a spray meant to clean them. They do get dirty after a bit and need to be cleaned. If you have a washable air filter that can cause them to get dirty quicker because the oil coats them then dirt will stick to the sensor.

other options would be an air leak that is allowing air in but not being metered.

 

[Clydez7]

Have you cleaned the MAF sensor? They make a spray meant to clean them. They do get dirty after a bit and need to be cleaned. If you have a washable air filter that can cause them to get dirty quicker because the oil coats them then dirt will stick to the sensor.

other options would be an air leak that is allowing air in but not being metered.
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Yes cleaned it and iac. I have used a vacuum gauge to eliminate it being clogged cats. Don't wanna keep replacing sensors that don't need replacing. I'm piecing together everything needed to do a 5.0 explorer swap with a t5 but need it to run a couple of weeks yet.

 

[Clydez7]

I've also sprayed around the engine compartment with starting fluid trying to find any air leaks and found nothing.

 

[Bgunner]

is the MAF on the air cleaner box or on the intake manifold? I'm more familiar with the older 3.0's but the intake tube would develop cracks from age and would let air in to the intake tube after the MAF sensor on the air cleaner box. IF your maf is on the manifold then this is not an issue for you.

 

[Curious Hound]

is the MAF on the air cleaner box or on the intake manifold? I'm more familiar with the older 3.0's but the intake tube would develop cracks from age and would let air in to the intake tube after the MAF sensor on the air cleaner box. IF your maf is on the manifold then this is not an issue for you.

On a 99, I'm pretty sure it's over by the air cleaner. It is on my 93 and I know it was on the 2001 that I robbed an air filter housing from.

 

[Clydez7]

is the MAF on the air cleaner box or on the intake manifold? I'm more familiar with the older 3.0's but the intake tube would develop cracks from age and would let air in to the intake tube after the MAF sensor on the air cleaner box. IF your maf is on the manifold then this is not an issue for you.

The filter box.

 

[Clydez7]

I have taken it off and checked it pretty good. The intake tube that is. Could it be the iac. When I cleaned it it had no gunk or build up.

 

[rubydist]

What are the stored codes?

 

[Curious Hound]

I would still recommend cleaning the MAF properly.

 

[Clydez7]

I will get some maf cleaner and clean it right and get a code reader while I'm in town. Stay tuned.

 

[Clydez7]

Thanks for the advise so far guys. OK so I had the codes read and the only thing was a p0401. Changed the egr vacuum solenoid. Already a new egr valve and dpfe sensor. It still has very noticeable stumble around 2500 rpm and above under load.

 

[rubydist]

The p0401 code is complaining about not enough egr flow, which usually is due to plugged lines where the egr gases should be flowing. That should have nothing to do with your stumble under high loads, because the egr should not be open under heavy loads. Given your description, it could be running too lean under load - that could be from the mafs not reading right or from vacuum leaks somewhere. Did you get the mafs cleaned?