I feel like I'm chasing my tail with this thing
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manicmechanic007
5 Year Member
I was assuming your base camshaft timing was correct
So, after resetting the timing belt (lined up correctly now) the problem was not solved yet then, right?
Not positive your Camry operates like a Ford but if the engine sees unmetered air the O2 goes lean
The processor adds fuel to make the mixture correct, that increases the idle speed
When the processor sees high idle speed and low TP volts it cuts some fuel to decrease the rpm
Then the process repeats and you get a surge due to the vacuum leak
Have you tried a bunch of propane at the rear of the motor both sides of that intake looking for an increase in idle speed?
Camry 4 pop with the intake in the rear is difficult at best to diag a intake air leak
The intake hose to the airbox is not cracked or split right?
That 99 has a maf and a baro too, right?
So, after resetting the timing belt (lined up correctly now) the problem was not solved yet then, right?
Not positive your Camry operates like a Ford but if the engine sees unmetered air the O2 goes lean
The processor adds fuel to make the mixture correct, that increases the idle speed
When the processor sees high idle speed and low TP volts it cuts some fuel to decrease the rpm
Then the process repeats and you get a surge due to the vacuum leak
Have you tried a bunch of propane at the rear of the motor both sides of that intake looking for an increase in idle speed?
Camry 4 pop with the intake in the rear is difficult at best to diag a intake air leak
The intake hose to the airbox is not cracked or split right?
That 99 has a maf and a baro too, right?
No MAF for the 4 banger in 99, only the 6 had it. And nothing really changed after straightening the timing belt except the high idle doesn't seem quite as high, it still surges while moving at 5 mph or more. I've not tried propane on anything, just used up what I had for carb cleaner and sprayed it all over the intake to head mating surfaces on the top but nothing underneath. As far as the intake hose goes, it all appears fine. I've ordered gaskets as you suggested and will be tackling that at some point soon. At this point it makes the most sense as it seems everything else is checking out fine. It also makes sense with what you just described but I'm having a bit of a hard time comprehending why it only surges at speeds above 5 mph and only gives a high idle condition below.
manicmechanic007
5 Year Member
Right, the moving vehicle part has me perplexed as well
That might make diagnosis a real pain in the ying yang
Is it a 5 speed or an automatic?
Some of the Fords with standard transmissions had strategy to hang the engine idle speed up a bit to aid in shifting so the car would not fall on its face in between shifts.
That might make diagnosis a real pain in the ying yang
Is it a 5 speed or an automatic?
Some of the Fords with standard transmissions had strategy to hang the engine idle speed up a bit to aid in shifting so the car would not fall on its face in between shifts.
It's a 5 speed and the surging while moving had me thinking of the VSS, which it probably IS producing the issue as you describe. Hopefully it'll be one of the intake gasket runners.....
It isn't related to coolant as I disconnected both of them. I think it's some part of the EVAC system, though I've not researched much more beyond that.
manicmechanic007
5 Year Member
I am not sure what that is without looking at the VECI and it may not even be on that VECI diagram, but it looks like an EGR transducer to me
That thermostat should be a 195 and with a 180 it will have an intermittent high idle
If that is a filter and it is plugged...
That thermostat should be a 195 and with a 180 it will have an intermittent high idle
If that is a filter and it is plugged...
I thought it was a little cold but everywhere I saw online said 180. Here's Rock Auto's selection for reference:
And O'Reilly's:
And that piece is a vacuum switch but I'm more focused on the intake gasket at this point. I picked up the new intake gasket last night after work, so I'll hopefully find out if that fixes it this weekend. I'm confident that it will given our conversation earlier in the thread. I had the same line of thought concerning the O2 sensors that you gave about the intake gasket but I didn't consider the gasket. I figured it was either a vacuum leak somewhere (which it most likely IS with a bad gasket....) or a bad O2 sensor. Since they're ~25 years old it wouldn't be a bad idea to replace them in hopes that it'll cure the problem and left it at that....
manicmechanic007
5 Year Member
The thermostat
Just about everyone will offer a 180 but it needs a 192 or so (all fuel injected cars need to be hot to operate properly)
So, all that I have seen use at least a 192 (Mercedes Audi, Porsche, Ford Chev, Dodge)
Toyota is where to get the stat
That might just fix the car... (getting a 195 thermostat in there)
Just about everyone will offer a 180 but it needs a 192 or so (all fuel injected cars need to be hot to operate properly)
So, all that I have seen use at least a 192 (Mercedes Audi, Porsche, Ford Chev, Dodge)
Toyota is where to get the stat
That might just fix the car... (getting a 195 thermostat in there)
I didn't do anything with the car this last weekend, but I did order a new downpipe/front converter. Something that I've not mentioned is that it has an exhaust leak at the flex pipe - nothing huge but it's enough to know it's there. I figured that at the very least it wasn't helping matters and maybe at most it's affecting the O2 sensors and causing issues. I'll see if I can't get this stuff done this week sometime....
Update: the new exhaust downpipe has been replaced. It's still doing the same stuff but it seems different, like it's not revving quite so high and the intervals have lengthened while it's surging. So I think it's been a combination of the exhaust leak and maybe the intake gasket is bad. Might try to attempt the intake gasket tonight after work. We'll see how the night goes, but I think that might just solve it.... 
Bailed on the gasket swap tonight. It's gonna be too involved for an after work project, so it'll have to wait til an available weekend.
Still haven't gotten anywhere with this, but I got my truck back so when I do I don't have to worry about getting back and forth to work. 
So I might finally attempt changing the intake gasket this weekend. The Cobra's fuel injection project is stalled and I don't have much more planned aside from moving stuff from my carport to a temporary portable garage so I can get some work done on the house. It's still doing the same stuff as before, I've just been living with it since I was down for a while after re-breaking my right ankle on New Year's Eve afternoon. It's now due for an oil change anyway and my buddy might be borrowing it since his long distance girlfriend will be in town for a couple weeks - that way she has her own mode of transportation instead of being reliant on him to go anywhere. So I'd like to at least attempt to get this issue solved beforehand.
Side note - I went ahead and tried a new VSS anyway - it made no difference.
Side note - I went ahead and tried a new VSS anyway - it made no difference.
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