Throwing Codes, Running Bad

[Macword]

I've had ongoing issues with my Terc...runs rough, suddenly loses power, gets it back again, surges, bucks, hesitates, and irritates me. I had a mechanic look it over...it didn't misbehave for him.

Here's what I've observed in codes on my Scan Gauge...any thoughts?

Codes I got a couple days ago:
P0401 (EGR Insufficient flow)

P0130 (O2 Circuit Malfunction Bank 1, Circuit 1)

P0133 ( O2Sensor Circuit Slow Response Bank #1 Sensor #1)

Codes I got today:

P0110 (Intake Air Temperature Circuit Malfunction)

P0170 Fuel Trim Malfunction - Bank #1

[96paseo]

Looks like you have a bad IAT sensor. Check to make sure its plugged in first. It plugs into the bottom of the air box. Also make sure there's no problems with the harness connector/wires. Have you cleaned the EGR? If you need the IAT, I have a spare I can mail to you for free. Just let me now via pm if you need it.

[Macword]

Thank you for your reply and offer. The IAT sensor had come unplugged. My son and I just cleaned the EGR valve, and the hoses and pipes connecting to it. I cleaned the inside of the air intake plenum where the EGR comes in.

It idles fine, but here's the problem that remains:

If you apply immediate throttle, it hesitates for several seconds (3 to 4) before starting to increase RPM. Once it 'catches' it sounds fine. In driving, it feels like it wants to stall bad, but never does. It just doesn't accelerate for several seconds when depressing the pedal. I would call it a 'bog'.

[96paseo]

Originally Posted by Macword

Thank you for your reply and offer. The IAT sensor had come unplugged. My son and I just cleaned the EGR valve, and the hoses and pipes connecting to it. I cleaned the inside of the air intake plenum where the EGR comes in.

It idles fine, but here's the problem that remains:

If you apply immediate throttle, it hesitates for several seconds (3 to 4) before starting to increase RPM. Once it 'catches' it sounds fine. In driving, it feels like it wants to stall bad, but never does. It just doesn't accelerate for several seconds when depressing the pedal. I would call it a 'bog'.

"Bog" does indeed sound like your problem. Have you replaced the fuel filter before? Maybe a little fuel starvation if its starting to clog up. You can check for a pressure drop across the filter and operating pressure if you have the equipment. The filter isn't that expensive so you may just want to change it if it looks old.

[Macword]

Yeah...it's a bog. But I did replace the fuel filter recently. So I've done spark plugs, new wires and boots, cleaned the EGR, stood on my head, and held my mouth just right.

I'm wondering if the distributor packs are intermittently bad. Also, I did change out the timing belt some months back...wondering about reprocussions from that too.

It's a mystery, but I want to get it fixed.

[Ru4wheel?]

What about those codes fpr the #1 O2 sensor? What does one do to test that? Has this one been changed, if so, how long ago? (I changed mine in my 96 and it made a big difference.)

[96paseo]

Ru4wheel brings up a good point. I replaced my upstream sensor at 186k and my downstream at 210k. IIRC, you have about 180k on yours. The timing may be right but its best to get it tested. You need to hook up a scanner( a good one $$$) that can tell you O2 sensor output voltages and compare them to spec. Its best to let a shop or dealer diagnose it. With the OBDII system, there are no test points in the underhood DLC to measure O2 sensor voltage. The lettering for them is there but no wires.