3.4 Engine hesitation after maintenance!

Hello everyone. As a birthday gift to my dad I did some service work to a new used truck he just bought. This weekend I worked on my dads newly acquired 3.4 2wd 2000 4runner sr5 automatic with 130,000 miles. My brother drove the vehicle home about 30 miles away and at interstate speeds with no mishaps 2 weeks ago! I replaced both rear axle seals and changed rear diff fluid first. My dad then drove around the block to verify everything was sound which it was. Pulled the runner into the garage to start the valve cover job.

I removed the entire intake manifold first. The intake manifold was coated with oily residue on the inside so my dad took them and used purple power to clean them up as I kept moving forward with removal of the valve covers. I cleaned the iacv and reinstalled with a new oem gasket while I was at it! I separated the throttle body from the intake manifold to do this.

After replacing spark plug tube seals, the rear camshaft caps, and valve cover gaskets both valve covers were reinstalled and new rubber/metal washers were used since the old ones were rock hard. I then shot some gum out carb+choke cleaner into the runners leading down to the intake valves to help clean up a bit. I removed the old spark plugs and used oem toyota plugs in their place! I reused the same ignition coils and ignition coil packs. I only had 1 new intake manifold gasket which I used to secure the lower intake manifold to the top of the cylinder head(s). I reused the other intake manifold gasket between the upper/lower intake manifold. A new toyota PCV valve with grommet was also fitted! I installed all necessary vacuum hoses etc in their original locations and proceeded to start the 4runner.

Upon starting the engine I could hear a vacuum leak and found that the vacuum hose from the iacv came off while installing the throttle body so I plugged it back in and vacuum leak is now gone. I got a code for the TPS sensor so I cleared it thinking it was from that loose vacuum line! The engine idles fine with no issues. The hesitation starts as soon as you try to give the vehicle 40%> throttle. I cleaned the maf sensor with maf cleaner. I checked for codes and got p0300 no "MIL" on so I removed the coil packs and the ignition wires to apply die-electric grease for the connections this didn't change anything.. Before my dad bought the runner there was a p0171 code stored. I cleared that code yesterday before starting the work listed above.

I am at a loss for what I touched that could cause this to be happening. Could the ignition wires be broken internally causing the p0300 code? I had to pull them at some extreme angles to maneuver them out/in while the intake manifold was still attached.. I ran a can of seafoam through the iacv and caused quite a bit of smoke to billow out from the exhaust. The engine is still acting the same as it did before the seafoam treatment!

Any ideas would be greatly appreciated! My dad hasn't registered the truck yet but I want it to be driveable when he does so in the next couple of weeks.

Thank you

 

Maybe try the plug wires. They're only like 50 bucks or so for oem. Also, maybe the spark plug gap?

 

I'm planning on getting the plug wires today. I did not check the gap on the plugs since I figured I gave the parts guy at Toyota my vin so the plugs "should" have been gapped for my specific application. I am going back to my dads on Thursday to check the spark plug gaps and install the new plug wires to see if that corrects the problem! I appreciate the response!

 

I just went thru alot of this , I had the P0120 TPS & P1300 No signal from igniter to ECM/Bank 1 & yeah, they use dental floss for high tension wire, but checking them is easy enough since we use that "waste spark" system, if your hesitation continues after all other issues resolved its possible that the butterfly valve in the throttle body has excessive clearance around the shaft/throttle body causing a random vaccum leak..

 

Yeah, with the iacv vacuum hose falling off during reassembly I got the p0120 code after I started it up! I'm hoping I can resolve this issue when I go back to my dads this Thursday. I'm taking my 3.4 Tacoma so I will be able to swap some known good parts to see if it changes anything... I still hope it is only incorrect spark plug gaps and the "old/brittle" ignition wires!

 

Is there any need to "burp" the iacv since it lost a little coolant in the process of removing it? I have been doing research and came across this little bit of info to help diagnose the problem: https://docs.google.com/viewer?a=v&...nxyYXlkb3VibGUzNjB8Z3g6Njc4OGU0NmU2NjA4ZDZmYQ I would like to think the maf meter is going out. Is it possible the TPS sensor could have been affected by the carb cleaner used to clean the throttle body?

 

***update***

I replaced the maf sensor and installed new ignition wires and the runner is running beautifully!

 

having an issue with the same ignition wires, pulling the p1300 code and no start, attached is a picture of the pack that has the disconnected wire, anyone know what wire it is? I cant locate a diagram for that pack, its the wire all the way on the right that came disconnected, any tips on how to fix? please help!