Question: I had my car in the shop to replace the valley-cover seal which was leaking oil, and to have the throttle body cleaned. I drive out and within about 10 mins of driving I get the Engine Fault/Poor vehicle Peformancewarning (limp mode)...never had this problem before.... I make it back to the mechanic and the codes being thrown are ignition coil codes (p0352, 353, 355, 358, and P1368). He tells me that the engine is running on only one bank of cylinders and suggests we open the ECU. We open it and find a capacitor leaking some fluid on the board (no other damage is evident). I had an ECU shop replace the capacitor but even with the new one, there is no change..the engine is still in limp mode, but it comes on and off as i'm driving (Ie: It constantly cycles from "normal" performance to "poor" performance). The mechanic thinks that it's still an ECU issue. The question is, are we going down the wrong trail into believing it's still an ECU issue? Is it possible that this problem can be caused by something he did while working on the car? I only say that b.c it seems way too coincidental that I bring it in for oil leak/throttle body cleaning, and now I drive out with a bad ECU? Thanks in advance for any insight..... [/align][/align]

 

Update: I'm pretty sure I hear a hissing noise coming from the TB...would this indicate a vacuum leak that could be causing my problems? Maybe when the mechanic opened it up to clean it he broke a seal?

 

yep, look for the leak on the bank that is missfiring.

 

I asked the mechanic and he said that if that were true, I would get a code for a Vacuum leak.... Also he said the problem would be constant...not intermittent like my case....

 

sorry guys, those are all ignition coil rpimary circuit faults, and since he put in cam cover gaskets(is that what you reffered to as valley gaskets cause ive never heard them called that) and the age of your car I can almost bet that the clips on the coils broke, he slid them on and they simple came unhooked while you were driving, and when this happens the ecu also shuts off the injectors for affected cylinders. pull the coil cover and I would recommend useing tie straps to hook each clip and tied to the adjacent coil to secure from now on. thats unless youde like to try and find all new connectors and or a harness. also I sure hope he inpsected the upper tensioners while he had the covers off since thats half the labor to replace the tensioners. if yours have never been done then they should have regardless off condition

 

Update: Shortly after I posted here I had an ecu-shop replace a couple of bad transistors on the ECM. For the first couple days the problem still existed...i was driving around town doing like 25mph tops (since I couldn't drive any faster using only half the cylinders). Then, all the sudden the engine fault warning vanished. A couple hours later the Check Engine light went off and I have not had a problem since. Months of trouble-free running...knock on wood. Also, I did have my tensioners replaced last year with the 3rd Gen. The ones that were replaced were 1st gen (with nearly 85K miles on them) and were in PERFECT condition. No cracks or wear or anything wrong with them. I was always careful about changing the oil and using synthetic. I'm convinced that poor engine maintenance is what led to most of the tensioner failures. IMHO

 

It's a miracle! Hallelujah.