Is This A Vaccuum Problem?

[jeepman]

I have a 97 Camry, auto, 144K that I bought new and has been taken very good care of. The problem is at low speed(10-30MPH) if you don't have to have much throttle(low rpm) I have what feels like a miss except it isn't a dead miss. In fact I thought it was a fuel filter but I changed that and I still have the same problem. It feels like it is surging very lightly. If I'm going about 10mph and it does this I can shift back to Low, get the rpm's up and it quits. It doesn't do it at highway speeds or under med. to heavy throttle. Since it seems to be a low rpm, low speed problem I was thinking maybe a vaccuum problem. Thanks in advance for any help.

[Kep]

It could be. You could probably verify it with a vacuum gauge.

Do you notice the problem more when the engine is hot or cold? Does it matter?

Before I spent a lot of money on parts I'd sure want to make sure that your emissions system is clean. Throttle body, EGR system, PCV, and (what the heck) IAC. Then do the Sea Foam routine (1/3 can in oil, 1/3 can in gas and 1/3 can sucked up into the brake booster vacuum tube). Afterwards, if it is still happening, there are some sensors that you could check.

Kep

[jeepman]

Doesn't seem to matter whether it's hot or cold but it seems to be alittle more pronounced when the motor has cooled some. What would a vaccuum gauge do and where would I need to hook it up to see if it is a leak?

[Eye8Pussies]

how is the idle?

[jeepman]

When I first start it cold the idle is high, about 12-1300rpm. It doesn't miss or chug and after it warms up it idles fine. On warm starts it also idles fine.

[toyomoho]

Any RPM change when surging?

[Kep]

Another thought, does it happen when the AC is off?

Kep

[jeepman]

Thanks guys for all your info so far. I'll check about when the AC is off. It definitely is more pronounced when cold and if the RPM's change it would be almost un-noticeable. I'll try describing it this way. It feels like if the brakes were grabbing and releasing(pulsing) or like on a manual transmission car when you lug the engine almost to the point of stalling how it will sort of jerk except not as pronounced.