Rough idle, missing and several trouble codes

My truck is a 1999 4.3 automatic with 140,000 miles. A few years ago I installed a K&N air intake kit and started getting a PO171 code. Well I took the MAF sensor off and cleaned it regularly because the oil from the filter was making it dirty. Well I ended up taking the K&N off and put it back stock because I got tired of getting the PO171 code. Well it went away for awhile and then the code came back. Well I kinda ignored it because the light would come on and then go back off and stay off for months. Well about a month ago while pulling in a parking lot the engine just died (the CEL was on). It did start right back up. It also had rough idle every once in awhile for the past 6 months. Well 3 days ago I was driving and the engine missed something its never done before. Now while driving the engine misses almost all the time. It will clear up and not missing for a few miles then go right back to missing. I just checked the codes and they are as followed PO300,PO301,PO302,PO305 and PO171. Any help would be much appreciated.

 

WELCOME TO THE FORUM...........

Now for your Taco, How long has it been since a timing belt was done on the engine ? Do you have the ability to do your own work ? Your combination of P0 codes could be from a bad camshaft angle sensor. Your last P0 171 couyld be a left over code if you turned off the check engine light by removing the battery terminal. You will turn off the light, but the code stays in the system till it is cleared. A little more info from you and we can answer things a little better for you. Good Luck.

 

Thanks Ga tacoguy for your response.



I fixed it today. The MAF was still very dirty. I took it back off and cleaned it with some choke/carb cleaner and a Q-tip. The choke/carb cleaner would not remove the grim that was on the MAF sensor. It took me carefully cleaning it with a Q-tip. This MAF sensor must have been dirty for a while because I can't remember it ever having this much power.

 

Well right after I posted it was fixed I drove to town and the miss in back. The truck has 140,000 and I don't think its every had a timing belt done. I am able to do all the work on the truck. We have a scanner to read and clear the codes. What's weird is when the truck is cold it usually don't miss. I can drive it to town which is 5-6miles away and it won't miss. I can turn the truck off at the store go in and come back out and it will be hard to start and barely idle and sometimes die and it will have a miss until I let it cool back off. I notice the miss is worse right at 1/8 throttle where I normal drive. I can press the throttle down and the miss won't go away but is just a little better.

 

I am sorry that you still have your problem. Did you get another P0171 code again ? You do need to change your timing belt, but this a lean condition on your drivers side of the engine. I believe you need to check this list of components for your engine code. Here is a link to them Just scroll down to the P0171 code and look at what they believe the problem is.

It could be the temperature sensor for the computer could be malfunctioning, but if you use the manuals that they have here you should get your answer. Good Luck.

 

I haven't got a P0171 code since I cleaned the MAF sensor. Thank you the links I will read them.

 

I'm no expert but from experience if you have not changed the o2 sensors in the 140 it might be time to do so. They are always (seemingly in my experience) the ones to foul up.