Jerking when acclerating
 

Basically this is a new problem for me. When accelerating at speeds of 30mph+, there is a hesitation that is noted. No check engine light is present, idle is good. I cleaned the MAF today, cleaned the throttle body, engine air filter is new. Has anyone experienced this before? With my luck, could it be the cats? Spark plugs are Bosch +4 (installed a few mos ago), ignition wires are STI and been on truck for 2.5 years.

Random thoughts:

clean throttle body again, throttle body cables binding, non-premium gas, fuel pressure? Fuel filter and regulator are in the tank, where the same sediment and crud in the gas is much harder to deal with (compared to a D1 with external regulator and filter). There is a schrader pressure test valve, but it is hidden under one corner of the engine. Drawing attached from RAVE.

Don't belive the cats would be at issue if no codes. Lot of ECU time is spent monitoring them. Info attached.

Fuel system cleaner like BG 44, SeaFoam, etc. add to gasoline if you are un-sure about the quality of gasoline used over a period of time. SeaFoam induction cleaning (some like it, some don't) is very exciting the first time you do it, smokes like mad for a few minutes.

fuel/air/spark... wires should be good if only a few years old, just make sure they are all properly seated on the plugs and didnt burn on the headers, but either condition would probably yield rougher running down low too. if the air and maf are good too, id check to see how dirty your throttlebody plate is, but even thats a long shot incase its getting sticky or fouling from buildup at certain angles... and as long as your airfilter is good, check for vacum leaks would be my next quick check.

that should only take a few minutes to do all that, then id check belt tension and finally, hows the tranny? check for visual leaks, and then the level.

is it a hesitation like just a time delay from gas to when the rpm's start movin north? or is there any jerking, sputteryness or slipping sensation like the engines revving up, but the speeds taking a few seconds longer to match? does it happen in every gear or just in auto while shifting?

just some quick thoughts to start

you said you cleaned your MAF.. you are not suppose to clean the MAF. you may have damaged this. I know some will say it can be done, but in truth it should not be done. More times than not damage is done and it can result in your issue. If yo have another MAF I would swap it out and run a check.

IMHO you can clean them. like anything else electronic, with correct chemicals and methods. Where many have problems is doing this when sensor is not stone cold first thing in the morning before cranking today. Spraying a solvent of any type with propellant will cause things to cool off quickly. Part of the MAF is pre-heated, and thermal shock on very thin components is not a good idea. That said, I saw a good looking one at the junk yard for my D1 and got it as a $20 spare. A new one cost more than what some guys have paid for their older trucks.

If MAF is toast, it will throw codes also.

I would wet down your plug wires, tonight when it is dark and while the engine is running, wiggle them with a stick and look for sparks.
As for the MAF, never just clean it to be cleaning it, our specific MAF doesn't take to it well like many other MAF's. there are 2 or 3 other auto manufacures that use this specific MAF and they all have the same problem, clean them and you stand a better then 50% chance of killing it even if you follow directions.

As always thank you all for the wise advice. I know I shouldn't clean the MAF, but I figured what the hell..the throttle plate was not too bad, but cleaned anyways. I had a new air filter housing cover replaced also because the old one was cracked and clips broken thanks to the alignment shop doing a "courtesy check". It was better after the cleaning but still noticeable. I did not drive the truck to work today so tomorrow I will check the trans fluid level-should be good, just got the truck back from the rear main seal replacement..which is good so far after 550 miles so far. I will check fuel pressure also. If all check out, then I will do an induction cleaning. I use Chevron, 76, Shell most of the time, then Sam's club gas in between and of course, always 91 octane.

Don't do SeaFoam induction cleaning indoors, or near an open door where smoke can be pulled inside the building. Lots of 'skeeters will die!

Do you know how to check your ATF level?

Pretty sure, we have serviced the transmission twice, I will look up the work instructions to make sure. I believe you check when warm, remove fill plug, some fluid should come out if it is full? Again, I will refer to Mitchell and Alldata to confirm the proper procedure. Thanks!