jmuir

Hey guys, new to the forum here - have found some great info here so far but hit a road block and need some more help.

I bought a 98' SR5 a couple weeks ago, and got a great deal on it - knowing that it had 'weak throttle response', as was clear when I test drove it. Didn't matter to me, as the rest of it was in awesome shape and the price was right

Anyways, here's a short list of what I've done so far - yet still have response issues (very sluggish on cold start, and just slow to respond in general, especially going up hills....also crappy gas mileage)

1. Filled it with premium fuel and added injector cleaner - MAYBE helped marginally

2. Cleaned throttle body - wasn't dirty/didn't help

3. Tightened throttle cables - didn't help

4. Replaced all 6 plugs and wires - definitely needed replacing anyways, but didn't help

5. Checked timing belt - no cracks, doesn't need replacing imo.



From my internet research, I've come up with a couple possible issues that it might still be:

1. Clogged CAT

2. O2 sensor

3. Bad fuel pump


Now here's the catch - the last owner cleared all the codes, so no lights on the dash are on.


Anyone have any suggestions? Living in Canada, I could just remove the CAT with no legal issues...but don't know how that would effect the O2 sensor


I have a couple pretty mechanically inclined friends who would do work for me - just trying to avoid taking it into the dealership to have them run a diagnostic and tell me things I already know


Any help would be much appreciated, thanks!

Jomoka

Could also have a bad or dirty MAF sensor. Does it have a K&N filter on it?

When I got my manual '99, it had a CEL on, and some lousy throttle response. Push the pedal down, there was a delay before power came on, and when you lifted it would hang on for a half second or so. Which made driving a stick shaft smoothly fairly difficult.

Turns out the overoiled K&N filder had fouled the sensor. Cleaned it off, cleared the CEL, and the throttle response issues were gone, and the CEL never came back.

vasinvictor

iTrader: (3)

Get a vacuum gauge. Rent or buy. They're cheap.

A healthy motor will have 16-20 in/hg of vacuum at idle.

You can use vacuum gauge to check for clogged cat. Check youtube on how to test for a clogged cat using a vacuum gauge. Don't just cut that sucker off on a whim. You can know.

A vacuum gauge will also let you know if your timing belt has slipped a tooth. (sounds likely based on your description) Again youtube test. You'll have low vacuum.

A bad o2 should light a sensor up pretty quickly.

You can rent a fuel pressure tester. Make sure it has a banjo bolt adapter in it. Again, don't just replace parts, especially a fuel pump because it's hard (unless you cut an access hole)