boomtown

Hello,

New to forum. Just purchased a used (57K) 2000 Chevy Express 3500 Cutaway Motorhome. When I am driving uphill under load, there is an groan/growl/vibration noise coming from the doghouse at about 2800 RPM. Only occurs under load and goes away once it shifts or I let off the throttle. Does not happen in 1st but rarely rev that high in 1st. No check engine light or apparent loss of power. Just not a friendly noise. Had the tranny serviced at an independant Trans shop and asked them to check it out. They road tested and said all is good. Thing runs great otherwise. Anyone had this symptom? Thanks for your help.

canucklehead

have you tuned it up and checked for codes? There may be a code without a cel.
It sounds like maybe a bad spark plug, or maybe a weak spark. Check under the dizzy cap for corroded points on the 8 poles inside and the end of the rotor.....I have to clean mine once a year. A weak spark might be letting you down when it lags under load....it might be getting rich on you and the weak spark cant handle it......

boomtown

Thanks. Probably could use a tune up. Had the doghouse off to install a tach and the dizzy cap had a date of '05 on it. The sound is odd. Sort of like Chewbaca. New to codes. Does the computer store all codes or do they only show up during the condition. When I had it smogged, the guy said there were no codes. Also, what is a good code reader to get?

canucklehead

The best code readers are the professional ones at the shops. Maybe you can find a shop that will check for you for free. Otherwise the OTC reader is good. Some are bs as they charge you a fee for diagnosis suggestions....

lunghd

This is the code reader I bought to use on my Express: Amazon.com : Professional Diagnostic Tool OBD2 OBD-II ELM327 ELM 327 V1.5 Bluetooth Car Diagnostic Interface Scanner Works On Android : Automotive Electronic Security Products : Car Electronics It cost me $9.19 w/ free shipping (using Amazon Prime) and can be used with a bluetooth enabled phone, laptop, pad or desktop.

The unit plugs right into the OBD port & you use your bluetooth capable smartphone for the interface.

There is also a free app - TORQUE -, that I use to monitor the engine while driving. It will also read & clear codes although I don't think it will read or clear ABS codes. You can track every sensor that the computer talks to plus engine rpms, est fuel mileage, etc. It does everything the mid & low level code readers do for a fraction of the price.<iframe class="pmdabdhezapbcnberfhz" style="width:120px;height:240px;" marginwidth="0" marginheight="0" scrolling="no" src="//ws-na.amazon-adsystem.com/widgets/q?ServiceVersion=20070822&OneJS=1&Operation=GetAdH tml&MarketPlace=US&source=ss&ref=ss_til&ad_type=pr oduct_link&tracking_id=anofrejeech04-20&marketplace=amazon&region=US&placement=B00EQ57B E8&asins=B00EQ57BE8&linkId=QWD47G6M763VVJ3F&show_b order=true&link_opens_in_new_window=true" frameborder="0">
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