Surging Engine plus....

[Mark90TC]

Okay, I'm finally getting some use out of my TC and finding some more problems. My dad is not known for regularly maintaining his vehicles.

One solution that I was given on the Lincoln EGroups was related to transmission problems. On hard accelerations, my TC was not operating smoothly. I went and had the transmission fluid flushed and changed and it's operating 100% now.

However, now I have come across another problem. I have a surging engine problem. The problem is not at idle but more at city speeds. I don't notice it so much on the highway. Looking through a booklet that goes along with a video tape on auto troubleshooting, I am thinking it could be a failing Coolant Temperature sensor or a defective MAP sensor. Anybody else have this problem and any alternate suggestions?

Thanks!

Mark

[Lscman]

Did you find the problem?? Does your car have trouble codes, indicated by a yellow check engine light? If the surging is at idle and real light throttle, it is likely a dirty Idle Air Bypass Valve on the throttle body assy. They have a wiring harness attached to them and they get carboned up and begin sticking and operating erratically. They will produce no error codes. You must unscrew it and remove for a thorough cleaning.

[Mark90TC]

Hi Lscman!

I haven't found the problem yet. I decided to bring it to the dealership because I had another problem that was not fixed properly when I brought my vehicle there for a safety check. I stumped them with my problem. They had my vehicle for 5 hours and didn't locate the problem. Their portable computer for testing while on the road was down and so they said they will have to rebook me when they get it back. He was looking at the fuel side of things and flushed the injectors and checked fuel pressure etc. but everything looked okay. The hesitation occurred more at slower speeds, but it will now also hesitate under full throttle. The full throttle problem seemed to go away for a while, but now it is back again. I did replace the the valve cover gaskets because they were leaking oil and after reassembling things, the engine seemed to work a little better for a while, but now it is as bad as ever.

I had checked for trouble codes myself, but didn't find any. I guess I will wait until the dealership gets their portable computer back. I will post their solution when it comes. I am tackling something a little easier. I picked up some front shocks today and will install them shortly.

Thanks again!

Mark

[Erik94Mark]

There is a small module attached to the distributor. It is called the TFI module. Just before these units go bad, syptoms such as surging, hesitation occur at part and full throttle. I have had this problem and replaced the TFI module and fixed it.

[Lscman]

Yes. It could be the ignition cutting out, since it occurs at various RPMs and throttle positions. The ignition is one of the few systems that isn't monitored and tracked very thoroughly via the EEC. It will often produce no error codes and no check engine light.

[Mark90TC]

Success finally!!

It was the TFI module and the pickup assembly. I tried just the TFI module but wasn't totally successful. Then after taking it back to the dealer, they replaced the pickup assembly and then all was fine.

I arranged for one more visit to the dealership to convert the A/C over to the new freon and hopefully that will be the last visit for a long time. I can finally begin to enjoy my TC now.

Thanks for the help!

Mark