Truck runs bad after plugs and MAF

Threw my new NGK plugs in and cleaned the mass air flow meter. Truck had been sitting overnight so when I started it up it was cold. Truck idled smooth as silk. Once it got up to operating temp while just idling it started to stumble. RPM's were bouncing around a bit.

Feels almost like the plug wire routing is wrong but I did them one at a time so they'd go back where they belong. I took a trip around the block and the truck does not run smooth. Lot's of shaking and hesitation. Made sure all the vacuum lines were hooked up too.

Any suggestions before I start shooting the parts cannon at it?

 

Did you gap them properly? I know it's a dumb question but they don't come properly gaped out of the box.

 

No I sure didn't. The scientist at NGK told me not too lol. Would the truck idle good when cold if the gap was off?

 

Not sure on that one sorry

 

Could be that one of the plug wires is loose. Reseat them and see.

 

I'm thinking it's the MAF. Try unplugging it and seeing if symptoms persist.

 

You did use MAF cleaner only....correct?

 

Maf

 

Yep, the CRC stuff

 

Unplug it with the motor running?

 

Checked them and all tight

 

No. Turn it off, unplug, start again, drive around. If it drives better when warm, the MAF isn't reading what it should because of an air leak or something wrong with the MAF itself.

 

Ahhh gotcha. That makes sense. I'll try that first thing in the am on my way to the parts store since the CEL came on during my third test drive. Thank you!

 

Just out of curiosity, is the Delphi brand in it now the only brand I should consider if I need a new MAF meter?

 

Did you pull the code(s) for the check engine light?

 

That's a bit beyond me, I'm not as experienced with these trucks as I'd like to be. OEM would be best, but I've never personally had issues with Delphi electronics. They may even be the OEM supplier, so some research would be my plan. YMMV.

 

I recall hearing somewhere, that you're suppose to disconnect the negative battery cable when you take the MAF out to clean it or if you're going to install a new one. That's what I've always done since hearing it from someone on TW.

 

Not yet. Had to get ready for work. I'll know something in the morning though

 

I heard the same thing. I'm paranoid about causing more damage when I'm working on this truck so I always take that precaution

 

When you first start the engine, it runs in Open Loop. Once it is warmed up it transitions to Closed Loop. These are ECU settings. Try disconnecting the ground cable on the battery for several minutes. This will reset the ECU. It will also clear the CEL.

I would start there before you start throwing fixes at it. If the problem persists and the CEL comes back, get the CEL read. The CEL code will give you a starting point to finding a solution.