A buddy of mine spent the last two nights doing some work on the car trying to fix my rough idle problems. We reworked the vacuum system and all that rat's nest under the UIM. Got everything hooked up like we thought it needed to be and put it all back together to find out. Started the car and the idle problem seemed to be fixed. It was sounding great with just a real smooth idle. So we took it for a test drive. While driving, the car just acts real real sluggish. It spools up and everything, but you can't give it gas, doesn't really go anywhere at all. As soon as you give it more than about 30% throttle, it starts cutting out like it's not getting the right amount of fuel or something. It kind of an annoying problem. The only thing we could think of is it's not getting enough back pressure (because we're running open downpipe in order to fix it, it'll be back on later tonight), the fuel pressure regulator isn't responding in the right way, or after reading other people's posts about similar stuff, maybe the fuel pump isn't responding correctly and it is just stuck on low pressure. We just can't figure it out. Let me know what anybody thinks.

 

Check your plug wires... if one of them comes loose you'll get similar symptoms. It happened to me the other day.

Can you rev it to redline slowly? Or does it die at a certian rpm?

 

Yeah that's kind of what I was thinking so I'm gonna check both plugs and the wires tonight. Yeah i can take it all the way up slowly. Takes some time, but it can reach every rpm. It just seems to correspond with the throttle. I don't know... we'll try some more stuff tonight and I'll everybody know.

 

IIRC, there is a high and low speed relay for the fuel pump.

 

Reset your ecu, check for codes.

 

what exactly is the iirc? it sounds relatively familira but i don't know what it stands for. we did some of the other things i was talking about: added back in the solinoid for the fpr, and built the exhaust for it so now it's got back presssure, but it's still got the hesitation at more than 30% throttle. thanks for all the feedback though guys... keep it comin

 

Don't know if it's related to this but check it out anyway - http://www.fd3s.net/3k_hesitation.html

 

Sorry......
IIRC= If I recall correctly.

 

I had something similar happen after rebuilding my engine. Turned out that by cranking the car with the fuel pump fuse out in order to build oil pressure, it kicked a fault (that was not displaying a check engine light) saying the fuel pump relay was bad. You can check for this by grounding the '10' pin and the 'GRND' pin in the diagnostics box and then watching your CEL for a code (I got code 51 by doing this...."fuel pump relay")
So I cleared the code by pulling the battery cable and pushing on the brake pedal, and after that everything was fine. The ECU simply wasn't letting the fuel pump kick to high-pressure mode.

Good luck!

 

okay so we changed some more stuff and adjusted a few more things, took it out for a little test drive and it was still hesitating... so we put it down for alittle while and worked on some other stuff and decided we'd just figure it out later. went back to it about 3 hours later and started it up. started sounding like it was clearing up some. gave it some throttle and it seemed to clear out some more. sounded real good at idle so we decided to take another drive. WORKS LIKE A CHARM! don't know what happened or what we did, but everything is all copasetic. we're looking into how exactly it's set up to figure out possible things that could've fixed the problem, and i'll let people know if we find anything.

 

After reading this thread, it makes me kinda ponder.

I've read a couple different threads about spark plug wires in particular, and the previous owner had given me a set of Taylor Pro wires, so I put em' in not long ago. They're real thick n' all, but I have read some negative things about them on some threads.

Is it possible, even after less than maybe 3,000 miles that they would cause problems like an irregular idle and SLIGHT hesitations under light throttle?

It boosts great, and still hauls bum whenever I take it out for a spin, but the irregular idle has me a tad worried. The boost/vacuum gauge doesn't seem to like it either. Compression test, coming soooooooon. o_O! Uhohz!