Weird sudder and backfire
 

When started in the morning my car shudders when I'm going down the driveway and backfires if I give it some gas. Just had the ignition coils replaced last year. Could it be the Mass air flow sensor causing the engine to think it's not getting enought air flow or vice versa, too much air? Please someone help me with some more options of how to fix this issue..Thanks

RE: Weird sudder and backfire
 

Model?

Unplug MAF connector to verify...

My guess is TPS, its structure is similar as in VGE, check http://www.cardomain.com/ride/748507/6

RE: Weird sudder and backfire
 

Well, I just replaced the MAF sensor this afternoon. It's actually my mom's car, so we'll see how it does in the morning. It usually only shudders and backfires in the morning on a cold start. Then after it gets warm, it's fine. Another thing though, all the time, cold start or not. It will not rev past about 5700 RPM. It used to go to about 6900 or 7 grand. I can't remember what the redline is but it doens't come close anymore. It's like it just runs out of juice @ around 5500. Any idea what this may be? It's a 2000 model...

RE: Weird sudder and backfire
 

"...on a cold start. Then after it gets warm, it's fine."
- TPS is used by ECU only when cold, after warmup it uses O2 feedback instead

- RPM problem can be in degraded rpm tachometer signal or gauge (more likely bad contacts). Check this link plus follow THE suggested links http://www.cardomain.com/ride/748507/14 (also p.10)

RE: Weird sudder and backfire
 

Yes thank you, I'm aware of that. But we're stuck with the piece of **** and that what I'm doing here...haha

Glad I drive an Audi, and not my mom's POS Nissan..ha

RE: Weird sudder and backfire
 

Alright, I appreciate it man, I'll look into it.