03 S-10 error P0101 AND P0420

[warwizard734]

Vehicle: 2003 S-10, V6, 40k miles
Problem: I got on the interstate a few days ago and the truck had a lot of trouble accelerating. The engine RPMs were getting way higher than normal for the speeds I was going, as if the truck was waiting too long to shift gears. Once I stopped accelerating it would calm down and drive fine.

My Service Engine light came on and Auto Advance gave me these two codes:
P0101
MAF or VAF
CKT Range/Perf

P0420
Catalyst Efficiency
Below Threshold
(Bank 1)

Background: I have only had the truck for a month. The day after I got it the light came on and it gave the MAF code. I bought some cleaner and cleaned the wires, the light did not come back on until last week. At this point the truck had begun misfiring very hard. I took it in and instead of the MAF code I got one about a cylinder 4 misfire. It turns out one of the spark plugs was not connected! The car drove fine for a week after that.

This weekend I have had that accelerating problem and the light has come on giving the two codes listed above.

I am not sure what to do. The lady at auto advance told me the second code was the 02 sensors. I didn't have her price those, but she priced the MAF at $162. If the MAF needs to be replaced I can do that myself.

If anyone has advice on my problem I would appreciate it. If you think the P0420 is the O2 sensors could someone indicate how difficult these are to change one's self? I do not know much about vehicles.

Thanks in advance.

[maxwedge]

Welcome to AF, focus on 101 first this can cause the cat problem, make sure there is no air entering the engine behind the maf, such as a vacuum leak or leaks in ducting between the maf and the throttle body. No K and N air intake correct?

[warwizard734]

I will inspect the MAF and throttle body. Perhaps I didn't get the hose sealed tightly when I put it back on after cleaning it.

I'm sorry, but what are N and K air intake?

[maxwedge]

Cold air high performance intakes, not a stock set up.

[warwizard734]

Oh got ya. I'm 99% sure it is all stock. I'm sure if anything like that was on it the seller would have tried to convince me the truck was worth more because of it.