'00 Camry LE 5SFE: Misses @ idle, hesitates on initial acceleration

[DougB]

Recently did a 200,000mi preventative maintenance overhaul on my '00 Camry which included:

Prep: Sprayed the engine with Simple Green and pressure washed it.

New timing belt
New A/C alternator belt
New P/S belt
New water pump & gasket
New thermostat & gasket
New spark plugs (NGK platinums)
New fuel filter
New air filter
New battery

Removed intake plenum & cleaned the hell out of it with Berryman B12
Removed throttle body* & cleaned the hell out of it with Berryman B12
*NOTE: IAC was removed from throttle body prior to cleaning. IAC was NOT cleaned.
Removed EGR valve and cleaned with Berryman B12
Removed and cleaned PCV valve

New plenum gasket
New throttle body gasket
New EGR valve gaskets

Removed & cleaned fuel rail and all four injectors with Berryman B12

Replaced all fluids (engine oil, A/T ATF, diff ATF, coolant, brake, Gatorade for me).

===========================================

As stated in the title, the car has now developed a few issues...
1) erratic occasional miss at idle whether running cold or hot
2) hesitation upon initial acceleration (usually accelerating off a dead stop), but perks right up after a few seconds

The car purrs at anything above 25mph with no issues cruising or accelerating at higher speeds. Fuel economy is great (~33mpg). No codes.

I'm guessing it could be one of several things:
A) Bad plug wire(s)
B) vacuum leak, most likely around the EGR
C) clogged fuel injector or, as I've read in another post, possibly a failing fuel pressure regulator

All the vacuum lines look to be in good shape and properly connected. The EGR looks like it's well seated, however, it was the biggest pain-in-the-ass to get back on the intake manifold. I struggled for about 1.5hrs to get it in place.

One of my plug wires refuses to snap down on the plug, but it's always been like that and I figure if it was an electrical problem it would be persistent and consistent at all speeds. If there was a problem with a fuel injector, I figure I'd see a reduction in fuel economy. My gut tells me it's the EGR.

I've been the cars caretaker for the past 10yrs. Prior to all this, the computer was throwing a code for vacuum (???) which I assumed was because the throttle body was so dirty.

Looking for some experienced input on this one. I don't want to chase this problem with more money than I have to.

TIA!

-DougB

P.S. The old timing belt with 200,000mi on it came off the car looking brand new. It was almost a shame to replace it.

[Stillrunning]

Originally Posted by DougB

Looking for some experienced input on this one. I don't want to chase this problem with more money than I have to.

Let me look into my crystal ball and pinpoint the problem for you.

[DougB]

Originally Posted by Stillrunning

Let me look into my crystal ball and pinpoint the problem for you.

Thanks for the clever response! Keep up the good work - you'll go far!

[Mike Gerber]

"Prep: Sprayed the engine with Simple Green and pressure washed it."

"One of my plug wires refuses to snap down on the plug, but it's always been like that and I figure if it was an electrical problem it would be persistent and consistent at all speeds."

With these 2 statements I would check to see if water got down in to that plug well and combined with old plug wires, it could be letting the spark to that plug short to ground inside that plug well. Have you checked down in that well for water? Have you tried blowing out that well with compressed air? Have you tried ohming out that wire? How old are these plug wires and are they OEM or aftermarket? The reason I ask is that I have seen aftermarket wires last as little as 1 year or 20,000 miles before causing problems.

Mike

[DougB]

Originally Posted by Mike Gerber

With these 2 statements I would check to see if water got down in to that plug well and combined with old plug wires, it could be letting the spark to that plug short to ground inside that plug well. Have you checked down in that well for water? Have you tried blowing out that well with compressed air? Have you tried ohming out that wire? How old are these plug wires and are they OEM or aftermarket? The reason I ask is that I have seen aftermarket wires last as little as 1 year or 20,000 miles before causing problems.

For reference, yes - I did blow out the wells with comp air. They also sat open for about one week while I tackled all the other stuff, so I'd guess if I missed any water it would've evaporated. I don't know the resistance ratings for the wires (haven't searched).

But you're right - the issue was the plug wires... last replaced in '03 with fewer than 75,000mi on the car.
As it was the lowest cost option and needed to be done anyways, I replaced the wires this morning with a new 5mm NGK set. The problem vanished.

Thanks Mike!

[Mike Gerber]

Glad you got the problem fixed. I would be willing to bet that if you ohmed the old wire set you would find 1 or 2 with no resistance at all. That would mean the wire(s) has an internal break somewhere.

Mike