Really Weird And Annoying Issues

[Paladin]

Well I see that there have been some who have had great luck with their aleros and others like me who havent. I recently purchased a 99 Alero (GL?) 2.4/automatic with 130,000 miles. All was well but then I started having really weird problems after I began with some intake/exhaust mods. I did a different cat back with a flowthrough muffler and a ran a short ram that is connected to the stock hose ( just removed airbox). After a couple of weeks I noticed a lope that got more and more pronounced. No vacuum leaks, and no other issues that were discovered by me or the GM mechanic that would indicate the cause of the lope. He later told me I had a bad coil, needed different plugs because Autolite Platinums were no good, and I needed a new bank 1 O2 sensor. He wanted $400 to do it. I did it myself for under $100. Problems still there and the OBD code 171 (too lean) comes up intermitently. Car misses slightly when rpms are below 1500 and engine is cold. Today I go for a short jaunt and on the way back home car starts missing really bad. I stopped at autozone and pulled the ignition control module and it tests bad. Bought a new ICM( didnt notice they gave me the wrong damn one) and installed. Car cranks but wont start, 2 hours of using a multitester shooting wires and checking continuity I notice that the old module pinout is different from the new one and get the correct one. I also notice that on the plug wire/coil pack housing that #3 and #4 have arced and burnt out some of the plastic at the base of the electrode, so I replaced that as well. I ohmed out the new coils I installed last week, got new wires and reassembled everything. Everything from the ICM to and including plugs is brand new or a week old, but car runs rougher than it did when I first stopped in, and its spewing molten stuff out my new exhaust. Well it turns out my cat was completly plugged so I punched a hole in it because it was already toast to see if it helped until I take it back to my friends exhaust shop tomorrow and still ran very rough, now loud as hell obviously because of the exhaust leak and would not idle. When it died it did so very violently and shook the car very badly. I have another appointment for this friday for it to go back to the shop, but quite honestly I am at a loss for what exactly is wrong at this point. All I know is that after roughly 6 hours (with the wife there also) and $400 later I keep fixing one thing only to find another and dont know why. Any ideas or help would be great. I have had people say timing and either a bad cam sensor, crank sensor, or maybe even the PCM is bad. ARRRRGGGHHHHHHHHH! I like the car, but damn this is crazy. Please HELP

[Paladin]

Well after installing the new cat today at my friends exhaust shop I pulled the plugs. It was only firing on 1 cyl all the time and 1 other intermittently. Pulled the brand new ICU and it tested bad. Needless to say the gal at autozone that gave me the wrong ICU yesterday hid from me and my wife after the other one tested bad. Going to a diff store to get one that already was tested and tested good and update on how it goes

[ptrudel]

that blows man...the arc-ing of 3&4 happened to me too actually

[Paladin]

Well still no luck, I went and picked up another ICM from a different autozone store. They checked the one I brought in and told me it was still good, but the funny thing was that they used a diff code in their machine than what they had used at the local store here. Anyways they still gave it to me considering I had just driven 35 miles to get it. Goes to Mr GoodWrench tomorrow a.m. for further troubleshooting and testing so with anyluck my pocketbook wont be to much lighter and problem will be solved :biggrin:

[doubleN0alero]

damn it just sounds like you're having all sorts of bad luck. I had the same problem with not running just right when I switched from a cai to a wai....sure enough, i switched it back and it hasn't ran this well in quite some time.

[Paladin]

I switched back to the stock airbox after the initial problems of reading to lean and still to no avail

[Paladin]

Well, according to what some have said and what I have read regarding my problem I may have narrowed it down finally. According to the Haynes manual and a couple of GM mechanics they think that my week old coils are bad. According to the guy at Autozone who initially checked the primary and secondary resistance of the coils they should read in between 6,000 and 9,000 Ohms on the secondary (cold). The manual and the GM guys said they should read .4 to .8 primary and 4,000 to 8,000 on the secondary. Too bad its locked up in the shop :shout: Guess I will just have to wait until monday morning and see if that's the issue :cry:

[Paladin]

UPDATE:

Well according to Mr Goodwrench, Crank sensor is showing bad, but he also thinks its the PCM, but was checking the timing chain as well. When I spoke to him a little while ago he thought maybe the PCM was throwing a bad code for the crank sensor, but will let me know everything for sure tomorrow a.m. Was hoping things would be quicker and easier, kinda wanted the ho back today :pissed:

[jlenko]

It sounds like you've got people blindly replacing stuff, without knowing what they're doing.

Has anyone used a Tech 2 to check the duty cycle on the injectors? If you're throwing a lean code... you could actually have a fuel delivery problem... aka, clogged injector (what did the plugs look like when they came out?). You might have a dirty fuel filter.

It seems more than a little suspect to me, that you've been thru ICM and PCM and they're being found to be bad... that's pretty hard to believe.

[Paladin]

ICM was erroneously tested bad, it's now back in. The PCM however was bad, and had that replaced along with coilpack housing again (#3 ohmed bad). The fuel filter is new today. The GM Mechanic tested line pressure, but was not there when he did it to know from what points pressure was tested just that he said it was good. I suspect that it was only tested with line capped at the fuel rail inlet fitting and not a complete circuit. He did remark the fuel pump was going bad, but dont get how that could be if the pressure was good :blink: He also stated that he pulled injectors and 1 did have some gunk which he cleaned up. So at this point the alero is home and his brother will be doing the fuel pump at some point this week. It runs, but still has a slight lope, and until its warm will stumble a little til you hit about 1600 rpms. I personally think that if the pressure is good but delivery to cylinder is bad, either the rail has some obstruction or it's a injector problem still. Guess we'll see later this week :pissed:

[Paladin]

All is well again :rolleyes2:. I replaced injectors last week and along with all of the upgrades and parts, it's running like a champ now :yahoo:

[cherrington17]

2 months later and another ho is revived. nice job pally!