Rough idle that becomes worse in drive, reverse

Alright, hey Joe (et al), I'm back. After finally getting the stripped stud bores drilled out and getting the Big-Serts put in and everything bolted back up the engine sounds a bit better and no longer has the gas-forward smell to it which is great.

The other side is that the significant/rough idle change when the vehicle is put into any gear is still present. I've checked the timing and idle again and have noticed that the idle seems too low when the engine is first started (even though it's set to 750-800 at operating temperature), either begins to stutter somewhat or sounds like it might, and takes a long while to smooth out despite the engine reaching operating temperature. Even still, it kind of sounds like there's a miss. If I drive the truck around the block a bit it speeds up the process of bringing the engine up to operating temperature. The truck starts up just fine so I don't believe its the Cold Start Injector. Perhaps the Idle Air Control Valve? I'm at a lost as to how many things have been replaced or fixed and the engine somehow still has issues.

The engine holds steadily at 5 degrees BTDC (terminals jumpered) and 12 degrees BTDC once warmed up sufficiently and moves around a little when still warming up.

What would effect the idle intensity when changed from neutral or park to drive or reverse? I'm on the hunt for a new detent cable because mine is overstretched and the transmission doesn't shift properly. Would this effect the idle smoothness? Is it time to light the truck on fire?

Hey Steve, the truck does run pretty fine except for the idle and a bit of sluggish shifting which I believe is related to the stretched detent/kickdown cable. Today I took it out and did what you said - I gunned it down streets! Haha. It was fun. I then took it to be smogged and the tech pushed it at 25MPH for a while as well. I noticed that the shifting, power and acceleration were all significantly better after my first jaunt and still good after the smog check. The truck failed the smog so tomorrow Tuc (the truck) is getting a new catalytic converter.

The current fuel is probably about three months old so when it runs lower I'll put in some fresh stuff and gun it some more as you suggested. Hopefully the idle gets even better; I realize it'll never be as smooth as modern cars which is fine. It's still too rough to be normal though and I'm plum out of ideas. I even changed the transmission mount hoping that was the problem because the old one was shot. At one point the idle was so severe I couldn't see out of the side mirror because everything was seriously blurred. It's tolerable now. I have seen Fords from the 1960's with smoother idles. I may just have to live with it or succumb to taking it into a shop. I have attached another video that I took today after the new exhaust manifold, O2 sensor, and speedy driving of today.

Update/Check In: The new catalytic converter is installed and I passed CA emissions! Woot Woot!

12/14: Idle is still rough and after driving about 35 miles on the freeway (at varying speeds). I noticed that the truck felt like it was lurching when I pulled in to park at my location. 6 hours later, the same thing. I thought maybe it was low on ATF so I put more in (it needed some) but no change in the lurching until I'd hit about 20-25 mph then it would feel more normal.

12/15: I installed a new 2-stage thermostat, new Coolant Temperature Sender (to ECU), and burped the cooling system well. The engine temp gets very slightly higher now but there's been no change in the idle or engine performance.

12/16: I pulled off the Auxiliary Air Control valve to make sure it was clean. I'd cleaned it really well when I rebuilt the engine but checked it again and it's still spotless. I also pulled off my air inlet hose and noticed a small amount of surface moisture and a few drops in the throttle-side elbow; the exterior was bone dry. The throttle body itself has a small amount of moisture as well, similar to the sheen/greasy feel of a surface after wiping coolant off of it well, but not also using brake cleaner or something so there is a slightly slick feeling.

So tomorrow I'm going to attempt to check the fuel pressure regulator and injector harness connections. Fingers crossed.

This idle issue is so strange. If I figure it out, hopefully it will save someone else a lot of headaches in the future.

Steve,

I'll do exactly as you suggested later today or tomorrow to narrow down the lurching/lunging motion and yes, I have put in new, higher octane fuel from 76.

I may have a definite clue about the idle problem. Yesterday I pulled off my EGR valve and modulator to clean them. The modulator had nice flow through each post and the filter pack looked pretty good. The EGR valve I continuously sprayed with carb cleaner and brake cleaner until it would become clear, then I'd scrub out as far as I could inside of each and repeat the process. I let it sit for hours with carb cleaner in each area and reinstalled it today. I first checked for vacuum and the diaphragm moved and seemed to hold just fine. When I pulled the vacuum hose off the valve and sucked on it while the engine was idling there was no response so apparently the valve is still dirty and is causing a vacuum leak.

Should I continue to soak it for another night? I felt like I got it pretty clean but apparently not clean enough. It's not an inexpensive part and it seems like cleaning it should work.

I actually blocked the EGR port at the intake manifold right after sending you the last message per the instructions at LC Engineering, 22RE specialists. It starts fine like usual and runs a tad smoother but nothing extreme. I'm going to go buy more carb cleaner tomorrow, remove the EGR again, and clean it for another 10+ hours. Ill also recheck the modulator per your instructions. My BVSV is new (I broke the nipples on the last one) and I sprayed brake cleaner through the metal pipes connecting the vacuum lines at both ends for both ports to the EGR. The cleaner was crystal clear and blasted right through.

My engine is still not coming up to operating temperature and after blocking the EGR it seems like the missing goes away or reduces significantly. I'm noticing that my cold-start idle is working but the engine never seems to drop back to a warm temperature idle. The idle actually seemed smoother but much too fast. Something is up with the engine not reaching operating temperature. The thermostat and sender to ECU are new, the upper radiator hose heats up slowly and gets hot, there are no leaks, and the heater in the truck gets hot. I burped the cooling system again and will do it one more time in hopes that there are still trapped air bubbles. The temperature gauge's position in the truck varies ever-so-slightly but barely moves past the minimum temp line. When it does it's only by about 1/8" which is too low, then it'll go back down to the minimum line and my previous thermo read the same.

I suppose testing the sender to gauge and ECU readings are next? I'm also looking into how to find out if my fan is turning on too soon. If the engine isn't coming up to temperature that could certainly be why the idle is rough and too fast.

Oh! I knew nothing of the jiggle valve on thermostats until I stumbled on a thread discussing position and temperature variance. I have no idea how I installed the thermostat in relation to the jiggle valve but it seems that having it installed correctly cools the engine down more so even if mine is not at the 6 o'clock position I'd have a warmer engine, not a cooler engine. I'm inclined to leave it for now.

I changed out the sender to the ECU which is the third picture with the green plug. It was pretty inexpensive so I just replaced it altogether.

I am thinking of pulling the sender to the gauge to check it, but honestly I doubt it’s that. I was looking for an IR thermometer last night and think I found one near by that’s affordable. I’ll shoot different parts of the cooling system when I get the thermometer and report back.

I believe the fan turns on (but doesn’t pull air) when the vehicle is started, regardless of temperature because it’s belt driven and on the same loop as the water pump, if I recall correctly. I was researching because my fan always turns on, I thought that maybe it’s indicative of a faulty fan clutch however I only found blogs saying it turns on regardless though I'm open to checking the fan as being the issue; I’m so perplexed by this idle issue.

I found some of the problem. I removed my fan and the clutch and the engine temp gauge came up to the level it used to years ago (second picture). The fan clutch is part of the problem. The idle feels smoother now most of the time but still much too fast, as though the computer isn't receiving the signal saying the engine is up to operating temperature.

The Cold Start Injector Timing Sender ohms at about 31 when cold and 55 when hot so it's within spec. I started the truck cold with the CST unplugged and it started only slightly worse so I'm going to check the Cold Start injector tomorrow to see if it's firing when cold.

The engine temperature gauge stayed nearly 100% steady for all of my driving which included the freeway and street. After a couple of errands I headed home and only then the gauge start to creep up, so I turned on the heat until getting onto the freeway and it came down to the normal level again, still without the fan installed. Once I got off of the freeway the gauge took longer to drop and made it to as high as a third of the way to red. Once I parked I let the truck idle and the gauge rose slowly until about halfway to red and then I turned the engine off.

The following are different temperature readings I got as the engine cooled. By the time I finished the temp gauge was at about 1/4 and still dropping so it's safe to say the thermostat, sender to gauge and sender to ECU are all working just fine.

First picture - after idling for 9 minutes.
Second picture - as high as the gauge went before heading home.
Third picture - the gauge after driving on the freeway and letting the truck sit and idle for a few seconds after getting home.

Thermostat Housing: 215
Thermostat Neck: 192
Upper Radiator Hose at thermostat housing side: 201
Upper Radiator Hose at radiator side: 152
Valve Cover: 167
Exhaust Manifold: 268

I wanted to post a follow-up for my initial question since I’d gone through so much (and received a lot of insight and help) to solve the really rough idle. Everything I did previously helped but didn’t cure the problem.

I ended up changing the fan clutch as well and the overcooling problem has stopped. Now the temp rises too high when I’m driving up hills and I’m nearly certain it’s the transmission - it’s on it’s way out and I’ll be swapping to a manual in the next few months.

I put in new OEM (Toyota) motor mounts yesterday and the truck is much smoother now. It feels like a normal idle. So, it was the mounts. When I took the old ones off they were both slightly compressed compared to the new ones and the rubber on one of the old ones had separated from the top. The key here is that in just looking at them while installed, they looked fine. So, lesson learned. I should’ve replaced them when I rebuilt the engine. Now I know and hope this helps someone else out in the future.

Mount part number is: 12361-65011.