yurizx6r

I've been having this problem on my 5.0 for awhile now, but it seems to be getting worse and worse. Originally when the car was cold when I was in 1st or 2nd gear at 1700 or 1800 RPMs the car would jerk and the idle could bob just a little (100 RPMs) mainly the thing was it would jerk.

I've replaced the MAF, TPS (calibrated to .98 volts), and IAC. I have no exhaust leaks either.

What is making me scratch my head is each time I swaped out a part it would fix it for a day and the car would run perfect. Now the problem is worse because when the car jerks the RPMs bob 200-400 RPMs. When the car is heated up it will either "solve" the problem or make it a little better. It does do it in 3rd, 4th, and 5th gear, but not often and not as bad. The only code I have showing is a neutral safety switch. Any suggestions?

2011scgt

it possible it's your temp sensor it's on the left front of the engine

camaroeater

First off, if you havn't done a tune up (plugs, wires, rotor) i would do it. Also, what you explain could be your TFI Module, maybe distributor. Maybe do a search on here for running a test on the fuel and spark.

mattdel

Ehhh, nope to all of the above. EGR position sensor. Likely not bad, just giving inaccurate readings because of a faulty EGR valve, causing the bucking. Depending on the failure of the EGR, could cause idle issues. Possibly not related though.

yurizx6r

I have new spark plugs and wires in it (less than 500 miles w/ gap set at .50), I have a temp sensor I could swap that out. Is there any way to test the EGR valve/position sensor, TFI moduel, and distributor? Also, I swapped out the IAC twice. The original IAC started up fine (probably worked fine to) @1200 then went to 750. The second one went to 750 immediately on a cold start. This newest one idles at 900 even after it's warmed up. Related... I'm not sure!?

mattdel

Run KOER tests first and report back with codes.

yurizx6r

Ok. I will do. It may take me until Sunday to get it done. I will also swap out the coolant temp sensor since I already have the part. Also, come to think of it normal operating temperature for this car is exactly in the middle of the gauge, and I have been having to put in water/coolant in it a lot lately (every few hundred miles). No signs of leaks and all the caps are new. Possibility? I know the coolant temp sensor going bad will do funny things to the foxbody. There are two of them right? Thank you for all your help guys!

yurizx6r

Swapped the coolant temperature sensor. Runs slightly cooler, but not the problem. Back to the drawing board. I'm waiting on my friend to help me with the KOER test. Probably Sunday.

yurizx6r

Ok I ran the test today. No codes. I did two things today. I test drove it and it started to do it bad, so I revved up the motor high and it seemed to help it. I also swapped out the distributor cap and rotor (doubt that it was the problem). Its been running fine ever since.... I also asked my uncle about it and he claimed that he had the same problem. According to him if you tap the EGR valve with a hammer it will loosen the carbon chips that build up in it. I told him that the EGR seemed to be working fine because the rubber diagram is opening and closing when you do the vacuum test on it. He said if it's really dirty take of the EGR valve and start it up for a second then shut it off before it throws codes and that will clean the carbon chips through the throttle body. Any thoughts?

mattdel

Seafoam.