I have a '97 Cobra with a 4.6 unmodified (106,000 miles). The check engine light has been on for months; the car is still running great! the Ford dealer diagnosed - IMRC failure and "ports". Their quote was exhorbitant. Another mechanic found "coolant coming from the exhaust" - either manifold bad or if not, heads would have to be pressure tested, etc. Codes from Autozone are PO174 and PO171. Then the "marvelous mechanic" who diagnosed the coolant coming from the exhaust said he is not comfortable working on such a car!! What is the likely culprit? We absolutely love the car and baby it ever so much. Such drastic repairs are a little disappointing, given our gentle use. If it is the manifold failure only, what would be a fair replacement price? Thanks in advance!
Those are system to lean codes on both bank 1 and bank 2. I would check for vacuum leaks for one, possible maf, oxygen sensors, etc. What lead to the Ford tech saying the IMRC's are bad? There should be a code for that as well. Also if you have someone rev the car past 3250 rpms, there are two black cables behind the back of the engine by the intake manifold. If those wiggle or shake at or around 3250, then the IMRC's should be working and opening up.
Cleaning the IMRC's are fairly simple, I'm almost retarded when it comes to working on cars, but I did it in 8 hours. Most can do it in 4 and the experienced can do it in 2. Do a google and you can find a few write ups. 2 warnings, Don't ever over torque any bolts. Don't drop anything into the ports.
I did over torque one bolt in the cover. Sucks trying to get a broken steel bolt out of an aluminum intake. One slip and threads are FUBAR.
Yeah, that sucks!!! I sold a 4.6L motor to a guy and I knew it ran, he changed the intake because he wanted a new one. He started it, ran for a couple seconds and locked up. He was furious at my company, but when we got it back, I had my worker tear it down in front of him, and there was a 10mm nut jammed between the piston and the block!!! He was still mad at us even though it was his fault. Lucky for us he paid cash!! So he didn't get his money back!!! That is why it is great that we can run every motor we sell!
