I may be able to borrow a scan tool this weekend. Where can I look to find out the parameters for each sensor? I am interested in O2s, IAC, MAS, knock counts. I need to no what is normal operation and what an extreme variation of each sensor will cause.

 

Is the fuel pump the original from 1990? Perhaps it can't keep up with the required "enriched" idle mixture needed until it goes into closed loop.

 

No, it is a Walbro 255hp. It is about two years old. The filter and fuel pump sock were replaced last year when I replaced the fuel sending unit.

 

I didn't notice if anyone suggested checking the coolant temp sensor.

If you want info on the "normal" sensor readings (your car is not stock, so things will not match exactly), check my online scanner guide.

http://members.aol.com/InjuneerZZ/ScanMast.htm

 

When I scanned it last, the cts read correctly. Wouldn't it set off the SES light? I thought these also determined when the fans come on. Both of my fans work correctly. Is it possible the parts store sold me the wrong CTS? This morning it was warmer and my car ran better. It seems that my car wants to chug and buck until it warms up. I can watch the temp guage and when it gets to about 140-160 it smooths out.

 

Sounds like the IAC to me. Usually if your IAC is weak or sticking, it can't compensate fast enough when you cut on the air....hence the stumbles and coming close to cutting off (This is a classic sign of a bad IAC). Try cleaning it first, and then see if you can borrow one from someone else to test it out.

 

Let me throw this out for discussion. Are the coolant hoses hooked up to the throttle body? The hoses help winter drivability. I've had several performance vehicles that would experience carb icing with symptoms similiar to what you described until they warmed up when the ambient temperature was below 40 degrees in Southern Cal.

 

I plan on cleaning the IAC passage tomorrow and examining the IAC itself. I figure I am going to need to buy one in the near future since it is 12 years old and I did have to clean oil out of the intake when I bought the Engine. I don't know anyone I can borrow one from so that is out of the question. I am going to try to borrow a VOM and test my CTS.

No the hoses are not hooked up to the bottom side of the TB.

 

Update: Cleaned the tb and IAC and it helped a little.The IAC had what looked like carbon on it. I sprayed down the TB and cleaned it with Q-tips. This helped my bogging problem with A/C on and some of the hesitation. I can't seem to find anyone around here that will loan me a scantool. The local dealership won't scan my car(not that I could afford it) because of the engine swap. I think my IAC may be on the way out, but that can not be all my problem. Does anyone have a clue to why this happens when cold. I almost forgot that when I left the gas station earlier it bogged hard when I got on it a little and then picked back up. Could this be a CTS? I am open to suggestions.

 

Maybe it's the EGR valve or something...as far as i know this system works to adjust intake air when cold.

 

EGR has been removed and the PCM reprogramed to compensate. Can a cts still read right in a scan, but still be faulty? It really is beginning to look like it might be it.

 

If it's reading correctly, I don't know how it could be faulty.

 

I drove the car earlier and it is getting worse. Sometimes when I leave a stop light it falls flat on its face and almost dies. I am going to check plugs tomorrow. Still no SES(yes it does work). I almost forgot, my car takes forever to warm up. Could this have something to do with it. It is full of coolant and the thermostat seems to be working. What sensors are affected by low temps?

 

Replaced my plugs because they didn't look so good. I think I may have partially fouled them on initial startup. I started the car without the MAS and it was running rich. Reset my valves because I think I had a couple too tight. The car actually seems to idle better. Could this have been my problem? It wasn't as cold this morning so I didn't get to try it out in cold weather.